diff --git a/.github/workflows/ci_main.yml b/.github/workflows/ci_main.yml
index 519d69bb67..df5b59a338 100644
--- a/.github/workflows/ci_main.yml
+++ b/.github/workflows/ci_main.yml
@@ -23,7 +23,7 @@ jobs:
           node-version: ${{ matrix.node }}
       - name: install
         run: |
-          npm install -g npm@latest
+          npm --version
           npm ci
       - name: lint
         run: npm run lint
diff --git a/.github/workflows/ci_ts_latest.yml b/.github/workflows/ci_ts_latest.yml
index ab207255d6..1151427613 100644
--- a/.github/workflows/ci_ts_latest.yml
+++ b/.github/workflows/ci_ts_latest.yml
@@ -3,6 +3,8 @@ name: CI (ts@latest)
 on:
   pull_request:
     types: ['opened', 'reopened', 'synchronize']
+    # Legacy v7 is incompatible with latest TS
+    branches-ignore: ['7.x']
 
 permissions:
   contents: read
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8f6c7283e3..0b681e2abb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+## [7.8.2](https://github.com/reactivex/rxjs/compare/7.8.1...7.8.2) (2025-02-22)
+
+### Bug Fixes
+
+- **animationFrameScheduler:** some tasks are never flushed and sometimes it breaks completely ([#7444](https://github.com/reactivex/rxjs/issues/7444)) ([8bbfa4e](https://github.com/reactivex/rxjs/commit/8bbfa4efd15f6572316d5b2b05b2f49ded69a3ca))
+- **mergeWith:** works correctly with an Array ([#7281](https://github.com/reactivex/rxjs/issues/7281)) ([27855c6](https://github.com/reactivex/rxjs/commit/27855c635ca74107352ae3336944433a328c0b41))
+- **subscriber:** strict type signature for next method ([#7172](https://github.com/reactivex/rxjs/issues/7172)) ([0e2ef5e](https://github.com/reactivex/rxjs/commit/0e2ef5e1142699b028bc3624aae9b24c3e3aaccf))
+
 ## [7.8.1](https://github.com/reactivex/rxjs/compare/7.8.0...7.8.1) (2023-04-26)
 
 ### Bug Fixes
diff --git a/docs_app/content/guide/glossary-and-semantics.md b/docs_app/content/guide/glossary-and-semantics.md
index 882d516417..e10fba36c5 100644
--- a/docs_app/content/guide/glossary-and-semantics.md
+++ b/docs_app/content/guide/glossary-and-semantics.md
@@ -34,7 +34,7 @@ There are specific actions and events that occur between major entities in RxJS
 
 ### Subscribe
 
-The act of a [consumer](#consumer) requesting an Observable set up a [subscription](#subscription) so that it may [observe](#observation) a [producer](#producer). A subscribe action can occur with an observable via many different mechanisms. The primary mechanism is the [`subscribe` method](/api/index/class/Observable#subscribe) on the [Observable class](/api/index/class/Observable). Other mechanisms include the [`forEach` method](/api/index/class/Observable#forEach), functions like [`lastValueFrom`](/api/index/function/lastValueFrom), and [`firstValueFrom`](/api/index/function/firstValueFrom), and the deprecated [`toPromise` method](/api/index/class/Observable#forEach).
+The act of a [consumer](#consumer) requesting from an Observable to set up a [subscription](#subscription) so that it may [observe](#observation) a [producer](#producer). A subscribe action can occur with an observable via many different mechanisms. The primary mechanism is the [`subscribe` method](/api/index/class/Observable#subscribe) on the [Observable class](/api/index/class/Observable). Other mechanisms include the [`forEach` method](/api/index/class/Observable#forEach), functions like [`lastValueFrom`](/api/index/function/lastValueFrom), and [`firstValueFrom`](/api/index/function/firstValueFrom), and the deprecated [`toPromise` method](/api/index/class/Observable#forEach).
 
 ### Finalization
 
@@ -78,11 +78,11 @@ The act of one [producer](#producer) being [observed](#observation) by **many**
 
 ### Unicast
 
-The act of one [producer](#producer) being [observed](#observation) **only one** [consumer](#consumer). An observable is "unicast" when it only connects one [producer](#producer) to one [consumer](#consumer). Unicast doesn't necessarily mean ["cold"](#cold).
+The act of one [producer](#producer) being [observed](#observation) by **only one** [consumer](#consumer). An observable is "unicast" when it only connects one [producer](#producer) to one [consumer](#consumer). Unicast doesn't necessarily mean ["cold"](#cold).
 
 ### Cold
 
-An observable is "cold" when it creates a new [producer](#producer) during [subscribe](#subscribe) for every new [subscription](#subscription). As a result, a "cold" observables are _always_ [unicast](#unicast), being one [producer](#producer) [observed](#observation) by one [consumer](#consumer). Cold observables can be made [hot](#hot) but not the other way around.
+An observable is "cold" when it creates a new [producer](#producer) during [subscribe](#subscribe) for every new [subscription](#subscription). As a result, "cold" observables are _always_ [unicast](#unicast), being one [producer](#producer) [observed](#observation) by one [consumer](#consumer). Cold observables can be made [hot](#hot) but not the other way around.
 
 ### Hot
 
@@ -138,7 +138,7 @@ An [observer](#observer) that lacks all necessary [notification](#notification)
 
 ### Unhandled Errors
 
-An "unhandled error" is any [error](#error) that is not handled by a [consumer](#consumer)-provided function, which is generally provided during the [subscribe](#subscribe) action. If no error handler was provided, RxJS will assume the error is "unhandled" and rethrow the error on a new callstack or prevent ["producer interference"](#producer-interface).
+An "unhandled error" is any [error](#error) that is not handled by a [consumer](#consumer)-provided function, which is generally provided during the [subscribe](#subscribe) action. If no error handler was provided, RxJS will assume the error is "unhandled" and rethrow the error on a new callstack to prevent ["producer interference"](#producer-interference).
 
 ### Producer Interference
 
diff --git a/docs_app/content/navigation.json b/docs_app/content/navigation.json
index 58a9ac6236..f7de1552d5 100644
--- a/docs_app/content/navigation.json
+++ b/docs_app/content/navigation.json
@@ -120,6 +120,10 @@
     }
   ],
   "docVersions": [
+    {
+      "title": "next",
+      "url": "https://next.rxjs.dev/"
+    },
     {
       "title": "stable",
       "url": "https://rxjs.dev/"
diff --git a/docs_app/src/index.html b/docs_app/src/index.html
index 81ce43626e..92a1c8c9bd 100644
--- a/docs_app/src/index.html
+++ b/docs_app/src/index.html
@@ -84,7 +84,7 @@
   <script>
     if (!Object.assign) {
       // polyfill other non-evergreen browsers in a blocking way
-      var polyfillUrl = "https://cdn.polyfill.io/v2/polyfill.min.js?features=default,Array.prototype.find&flags=gated&unknown=polyfill";
+      var polyfillUrl = "https://cdnjs.cloudflare.com/polyfill/v2/polyfill.min.js?features=default,Array.prototype.find&flags=gated&unknown=polyfill";
 
       // send a blocking XHR to fetch the polyfill
       // then append it to the document so that its eval-ed synchronously
diff --git a/docs_app/tools/transforms/angular-api-package/index.js b/docs_app/tools/transforms/angular-api-package/index.js
index 294980b47a..d3bd330fe4 100644
--- a/docs_app/tools/transforms/angular-api-package/index.js
+++ b/docs_app/tools/transforms/angular-api-package/index.js
@@ -9,6 +9,7 @@ const Package = require('dgeni').Package;
 
 const basePackage = require('../angular-base-package');
 const typeScriptPackage = require('dgeni-packages/typescript');
+// prettier-ignore
 const { API_SOURCE_PATH, API_TEMPLATES_PATH, MARBLE_IMAGES_PATH, MARBLE_IMAGES_WEB_PATH,
   requireFolder } = require('../config');
 
@@ -21,7 +22,6 @@ module.exports = new Package('angular-api', [basePackage, typeScriptPackage])
   .processor(require('./processors/convertPrivateClassesToInterfaces'))
   .processor(require('./processors/generateApiListDoc'))
   .processor(require('./processors/generateDeprecationsListDoc'))
-  .processor(require('./processors/addNotYetDocumentedProperty'))
   .processor(require('./processors/mergeDecoratorDocs'))
   .processor(require('./processors/extractDecoratedClasses'))
   .processor(require('./processors/matchUpDirectiveDecorators'))
@@ -56,12 +56,7 @@ module.exports = new Package('angular-api', [basePackage, typeScriptPackage])
   })
 
   // Where do we get the source files?
-  .config(function(readTypeScriptModules, readFilesProcessor, tsParser) {
-
-    // Tell TypeScript how to load modules that start with `@angular`
-    tsParser.options.paths = { '@angular/*': [API_SOURCE_PATH + '/*'] };
-    tsParser.options.baseUrl = '.';
-
+  .config(function (readTypeScriptModules) {
     // API files are typescript
     readTypeScriptModules.basePath = API_SOURCE_PATH;
     readTypeScriptModules.ignoreExportsMatching = [/^[_ɵ]|^VERSION$/];
@@ -76,83 +71,22 @@ module.exports = new Package('angular-api', [basePackage, typeScriptPackage])
       'webSocket/index.ts',
       'testing/index.ts'
     ];
-
-    // API Examples
-    readFilesProcessor.sourceFiles = [
-      {
-        basePath: API_SOURCE_PATH,
-        include: API_SOURCE_PATH + '/examples/**/*',
-        fileReader: 'exampleFileReader'
-      }
-    ];
   })
 
   // Configure jsdoc-style tag parsing
-  .config(function(parseTagsProcessor, getInjectables) {
+  .config(function (parseTagsProcessor, getInjectables) {
     // Load up all the tag definitions in the tag-defs folder
     parseTagsProcessor.tagDefinitions =
         parseTagsProcessor.tagDefinitions.concat(getInjectables(requireFolder(__dirname, './tag-defs')));
   })
 
-  // Additional jsdoc config (for RxJS source)
-  .config(function(parseTagsProcessor) {
-    parseTagsProcessor.tagDefinitions.push({ name: 'owner' });
-    parseTagsProcessor.tagDefinitions.push({ name: 'static' });
-    parseTagsProcessor.tagDefinitions.push({ name: 'nocollapse' });
-    // Replace the Catharsis type parsing, as it doesn't understand TypeScript type annotations (i.e. `foo(x: SomeType)`), with a simpler dummy transform
-    const typeTags = parseTagsProcessor.tagDefinitions.filter(tagDef => ['param', 'returns', 'type', 'private', 'property', 'protected', 'public'].indexOf(tagDef.name) !== -1);
-    typeTags.forEach(typeTag => typeTag.transforms[0] = function dummyTypeTransform(doc, tag, value) {
-      var TYPE_EXPRESSION_START = /^\s*\{[^@]/;
-      var start, position, count, length;
-
-      var match = TYPE_EXPRESSION_START.exec(value);
-      if (match) {
-        length = value.length;
-        // the start is the beginning of the `{`
-        start = match[0].length - 2;
-        // advance to the first character in the type expression
-        position = match[0].length - 1;
-        count = 1;
-
-        while (position < length) {
-          switch (value[position]) {
-          case '\\':
-            // backslash is an escape character, so skip the next character
-            position++;
-            break;
-          case '{':
-            count++;
-            break;
-          case '}':
-            count--;
-            break;
-          default:
-              // do nothing
-          }
-
-          if (count === 0) {
-            break;
-          }
-          position++;
-        }
-
-        tag.typeExpression = value.slice(start + 1, position).trim().replace('\\}', '}').replace('\\{', '{');
-        tag.description = (value.substring(0, start) + value.substring(position + 1)).trim();
-        return tag.description;
-      } else {
-        return value;
-      }
-    });
-  })
-
-  .config(function(computeStability, splitDescription, EXPORT_DOC_TYPES, API_DOC_TYPES) {
+  .config(function (computeStability, splitDescription, EXPORT_DOC_TYPES, API_DOC_TYPES) {
     computeStability.docTypes = EXPORT_DOC_TYPES;
     // Only split the description on the API docs
     splitDescription.docTypes = API_DOC_TYPES;
   })
 
-  .config(function(computePathsProcessor, EXPORT_DOC_TYPES, generateApiListDoc, generateDeprecationListDoc) {
-
+  .config(function (computePathsProcessor, EXPORT_DOC_TYPES, generateApiListDoc, generateDeprecationListDoc) {
     const API_SEGMENT = 'api';
 
     generateApiListDoc.outputFolder = API_SEGMENT;
@@ -180,17 +114,17 @@ module.exports = new Package('angular-api', [basePackage, typeScriptPackage])
     });
   })
 
-  .config(function(templateFinder) {
+  .config(function (templateFinder) {
     // Where to find the templates for the API doc rendering
     templateFinder.templateFolders.unshift(API_TEMPLATES_PATH);
   })
 
-  .config(function(embedMarbleDiagramsPostProcessor) {
+  .config(function (embedMarbleDiagramsPostProcessor) {
     embedMarbleDiagramsPostProcessor.marbleImagesPath = MARBLE_IMAGES_PATH;
     embedMarbleDiagramsPostProcessor.marbleImagesOutputWebPath = `/${MARBLE_IMAGES_WEB_PATH}`;
   })
 
-  .config(function(convertToJsonProcessor, postProcessHtml, API_DOC_TYPES_TO_RENDER, API_DOC_TYPES, autoLinkCode, embedMarbleDiagramsPostProcessor) {
+  .config(function (convertToJsonProcessor, postProcessHtml, API_DOC_TYPES_TO_RENDER, API_DOC_TYPES, autoLinkCode, embedMarbleDiagramsPostProcessor) {
     convertToJsonProcessor.docTypes = convertToJsonProcessor.docTypes.concat(API_DOC_TYPES_TO_RENDER);
     postProcessHtml.docTypes = convertToJsonProcessor.docTypes.concat(API_DOC_TYPES_TO_RENDER);
     postProcessHtml.plugins.push(embedMarbleDiagramsPostProcessor.process);
diff --git a/docs_app/tools/transforms/angular-api-package/processors/addNotYetDocumentedProperty.js b/docs_app/tools/transforms/angular-api-package/processors/addNotYetDocumentedProperty.js
deleted file mode 100644
index d9b69709f7..0000000000
--- a/docs_app/tools/transforms/angular-api-package/processors/addNotYetDocumentedProperty.js
+++ /dev/null
@@ -1,19 +0,0 @@
-module.exports = function addNotYetDocumentedProperty(log, createDocMessage) {
-  return {
-    docTypes: [],
-    $runAfter: ['tags-extracted'],
-    $runBefore: ['processing-docs', 'splitDescription'],
-    $process(docs) {
-      docs.forEach(doc => {
-        if (
-          this.docTypes.indexOf(doc.docType) !== -1 &&
-          !doc.noDescription &&
-          (!doc.description || doc.description.trim().length === 0)
-        ) {
-          doc.notYetDocumented = true;
-          log.debug(createDocMessage('Not yet documented', doc));
-        }
-      });
-    }
-  };
-};
diff --git a/docs_app/tools/transforms/angular-api-package/processors/addNotYetDocumentedProperty.spec.js b/docs_app/tools/transforms/angular-api-package/processors/addNotYetDocumentedProperty.spec.js
deleted file mode 100644
index e8037165f3..0000000000
--- a/docs_app/tools/transforms/angular-api-package/processors/addNotYetDocumentedProperty.spec.js
+++ /dev/null
@@ -1,60 +0,0 @@
-const testPackage = require('../../helpers/test-package');
-const Dgeni = require('dgeni');
-
-describe('addNotYetDocumentedProperty', function() {
-  let processor;
-
-  beforeEach(function() {
-    const dgeni = new Dgeni([testPackage('angular-api-package')]);
-    const injector = dgeni.configureInjector();
-    processor = injector.get('addNotYetDocumentedProperty');
-    processor.docTypes = ['test'];
-    processor.properties = ['description', 'name'];
-  });
-
-  it('should run at the right time', () => {
-    expect(processor.$runAfter).toEqual(['tags-extracted']);
-    expect(processor.$runBefore).toEqual(['processing-docs', 'splitDescription']);
-  });
-
-  it('should mark docs with no `description` property as "not yet documented"', () => {
-    const docs = [
-      {id: 'a', docType: 'test', description: 'some content' },
-      {id: 'b', docType: 'test', description: '' },
-      {id: 'c', docType: 'test' },
-    ];
-
-    processor.$process(docs);
-
-    expect(docs[0].notYetDocumented).toBeFalsy();
-    expect(docs[1].notYetDocumented).toBeTruthy();
-    expect(docs[2].notYetDocumented).toBeTruthy();
-  });
-
-  it('should ignore docs that do not match the specified doc types', () => {
-    const docs = [
-      {id: 'a', docType: 'other', description: '' },
-      {id: 'b', docType: 'other', shortDescription: '' },
-      {id: 'c', docType: 'other' },
-    ];
-
-    processor.$process(docs);
-    expect(docs[0].notYetDocumented).toBeFalsy();
-    expect(docs[1].notYetDocumented).toBeFalsy();
-    expect(docs[2].notYetDocumented).toBeFalsy();
-  });
-
-
-  it('should not mark documents explicitly tagged as `@noDescription`', function() {
-    const docs = [
-      {id: 'a', docType: 'other', description: '', noDescription: true },
-      {id: 'b', docType: 'other', shortDescription: '', noDescription: true },
-      {id: 'c', docType: 'other', noDescription: true },
-    ];
-
-    processor.$process(docs);
-    expect(docs[0].notYetDocumented).toBeFalsy();
-    expect(docs[1].notYetDocumented).toBeFalsy();
-    expect(docs[2].notYetDocumented).toBeFalsy();
-  });
-});
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/Annotation.js b/docs_app/tools/transforms/angular-api-package/tag-defs/Annotation.js
deleted file mode 100644
index 4e9c8714cb..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/Annotation.js
+++ /dev/null
@@ -1,4 +0,0 @@
-// A ts2dart compiler annotation that can be ignored in API docs.
-module.exports = function() {
-  return {name: 'Annotation', ignore: true};
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/docsNotRequired.js b/docs_app/tools/transforms/angular-api-package/tag-defs/docsNotRequired.js
deleted file mode 100644
index 8bc386388c..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/docsNotRequired.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = function() {
-  return {name: 'docsNotRequired'};
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/experimental.js b/docs_app/tools/transforms/angular-api-package/tag-defs/experimental.js
deleted file mode 100644
index 4f679b5c14..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/experimental.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = function() {
-  return {name: 'experimental'};
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/howToUse.js b/docs_app/tools/transforms/angular-api-package/tag-defs/howToUse.js
deleted file mode 100644
index a0d7968e07..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/howToUse.js
+++ /dev/null
@@ -1,11 +0,0 @@
-module.exports = function(log, createDocMessage) {
-  return {
-    name: 'howToUse',
-    deprecated: true,
-    transforms(doc, tag, value) {
-      log.warn(createDocMessage('Deprecated `@howToUse` tag found', doc));
-      log.warn('PLEASE FIX by renaming to `@usageNotes.');
-      return value;
-    }
-  };
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/ngModule.js b/docs_app/tools/transforms/angular-api-package/tag-defs/ngModule.js
deleted file mode 100644
index a80c7df32a..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/ngModule.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = function() {
-  return {name: 'ngModule'};
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/no-description.js b/docs_app/tools/transforms/angular-api-package/tag-defs/no-description.js
deleted file mode 100644
index 9a105df8db..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/no-description.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = function() {
-  return {name: 'noDescription', transforms: function() { return true; }};
-};
\ No newline at end of file
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/security.js b/docs_app/tools/transforms/angular-api-package/tag-defs/security.js
deleted file mode 100644
index 1351061d99..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/security.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = function() {
-  return {name: 'security'};
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/stable.js b/docs_app/tools/transforms/angular-api-package/tag-defs/stable.js
deleted file mode 100644
index cc689085c0..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/stable.js
+++ /dev/null
@@ -1,11 +0,0 @@
-module.exports = function(log, createDocMessage) {
-  return {
-    name: 'stable',
-    deprecated: true,
-    transforms(doc, tag, value) {
-      log.warn(createDocMessage('Deprecated `@stable` tag found', doc));
-      log.warn('PLEASE REMOVE - its value is now computed.');
-      return value;
-    }
-  };
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/suppress.js b/docs_app/tools/transforms/angular-api-package/tag-defs/suppress.js
deleted file mode 100644
index a2fe2ea19d..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/suppress.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = function() {
-  return {name: 'suppress'};
-};
\ No newline at end of file
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/syntax.js b/docs_app/tools/transforms/angular-api-package/tag-defs/syntax.js
deleted file mode 100644
index 45c5a53cf9..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/syntax.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = function() {
-  return {name: 'syntax'};
-};
\ No newline at end of file
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/ts2dart_const.js b/docs_app/tools/transforms/angular-api-package/tag-defs/ts2dart_const.js
deleted file mode 100644
index 68c43bb23b..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/ts2dart_const.js
+++ /dev/null
@@ -1,4 +0,0 @@
-// A ts2dart compiler annotation that can be ignored in API docs.
-module.exports = function() {
-  return {name: 'ts2dart_const', ignore: true};
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/usageNotes.js b/docs_app/tools/transforms/angular-api-package/tag-defs/usageNotes.js
deleted file mode 100644
index 2fe75c0977..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/usageNotes.js
+++ /dev/null
@@ -1,5 +0,0 @@
-module.exports = function() {
-  return {
-    name: 'usageNotes'
-  };
-};
diff --git a/docs_app/tools/transforms/angular-api-package/tag-defs/whatItDoes.js b/docs_app/tools/transforms/angular-api-package/tag-defs/whatItDoes.js
deleted file mode 100644
index 8b995890a9..0000000000
--- a/docs_app/tools/transforms/angular-api-package/tag-defs/whatItDoes.js
+++ /dev/null
@@ -1,11 +0,0 @@
-module.exports = function(log, createDocMessage) {
-  return {
-    name: 'whatItDoes',
-    deprecated: true,
-    transforms(doc, tag, value) {
-      log.warn(createDocMessage('Deprecated `@whatItDoes` tag found', doc));
-      log.warn('PLEASE FIX by adding the content of this tag as the first paragraph of the `@description` tag.');
-      return value;
-    }
-  };
-};
diff --git a/docs_app/tools/transforms/angular-base-package/index.js b/docs_app/tools/transforms/angular-base-package/index.js
index 1c01daadb4..764c265675 100644
--- a/docs_app/tools/transforms/angular-base-package/index.js
+++ b/docs_app/tools/transforms/angular-base-package/index.js
@@ -11,7 +11,6 @@ const Package = require('dgeni').Package;
 const jsdocPackage = require('dgeni-packages/jsdoc');
 const nunjucksPackage = require('dgeni-packages/nunjucks');
 const linksPackage = require('../links-package');
-const targetPackage = require('../target-package');
 const remarkPackage = require('../remark-package');
 const postProcessPackage = require('dgeni-packages/post-process-html');
 
@@ -22,7 +21,6 @@ module.exports = new Package('angular-base', [
   jsdocPackage,
   nunjucksPackage,
   linksPackage,
-  targetPackage,
   remarkPackage,
   postProcessPackage,
 ])
@@ -82,15 +80,6 @@ module.exports = new Package('angular-base', [
     writeFilesProcessor.outputFolder = DOCS_OUTPUT_PATH;
   })
 
-  // Target environments
-  .config(function (targetEnvironments) {
-    const ALLOWED_LANGUAGES = ['ts', 'js', 'dart'];
-    const TARGET_LANGUAGE = 'ts';
-
-    ALLOWED_LANGUAGES.forEach((target) => targetEnvironments.addAllowed(target));
-    targetEnvironments.activate(TARGET_LANGUAGE);
-  })
-
   // Configure nunjucks rendering of docs via templates
   .config(function (renderDocsProcessor, templateFinder, templateEngine, getInjectables) {
     // Where to find the templates for the doc rendering
diff --git a/docs_app/tools/transforms/target-package/index.js b/docs_app/tools/transforms/target-package/index.js
deleted file mode 100644
index 45eedf9c06..0000000000
--- a/docs_app/tools/transforms/target-package/index.js
+++ /dev/null
@@ -1,10 +0,0 @@
-var Package = require('dgeni').Package;
-
-module.exports = new Package('target', [require('dgeni-packages/jsdoc')])
-
-  .factory(require('./services/targetEnvironments'))
-  .factory(require('./inline-tag-defs/target'))
-
-  .config(function(inlineTagProcessor, targetInlineTagDef) {
-    inlineTagProcessor.inlineTagDefinitions.push(targetInlineTagDef);
-  });
diff --git a/docs_app/tools/transforms/target-package/inline-tag-defs/target.js b/docs_app/tools/transforms/target-package/inline-tag-defs/target.js
deleted file mode 100644
index bab4913018..0000000000
--- a/docs_app/tools/transforms/target-package/inline-tag-defs/target.js
+++ /dev/null
@@ -1,33 +0,0 @@
-/**
- * @dgService
- * @description
- * Process inline `target` block tags
- * (of the form `{@target environment1 environment2}...{@endtarget}`),
- * filtering out the blocks that do not match the active `targetEnvironments`.
- */
-module.exports = function targetInlineTagDef(targetEnvironments, log, createDocMessage) {
-  return {
-    name: 'target',
-    end: 'endtarget',
-    handler: function(doc, tagName, tagDescription) {
-      var targets = tagDescription && tagDescription.tag.split(' ');
-      var hasTargets = targets && targets.length;
-
-      try {
-        // Return the contents of this block if any of the following is true:
-        // * it has no targets
-        // * there are no targets stored in the targetEnvironments service
-        // * the block's targets overlap with the active targets in the targetEnvironments service
-        if (!hasTargets || !targetEnvironments.hasActive() ||
-            targetEnvironments.someActive(targets)) {
-          return tagDescription.content;
-        }
-      } catch (x) {
-        log.error(createDocMessage('Error processing target inline tag def - ' + x.message, doc));
-      }
-
-      // Otherwise return an empty string
-      return '';
-    }
-  };
-};
\ No newline at end of file
diff --git a/docs_app/tools/transforms/target-package/inline-tag-defs/target.spec.js b/docs_app/tools/transforms/target-package/inline-tag-defs/target.spec.js
deleted file mode 100644
index e01bf14ace..0000000000
--- a/docs_app/tools/transforms/target-package/inline-tag-defs/target.spec.js
+++ /dev/null
@@ -1,40 +0,0 @@
-var testPackage = require('../../helpers/test-package');
-var Dgeni = require('dgeni');
-
-describe('target inline-tag-def', function() {
-  var dgeni, injector, targetInlineTagDef;
-
-  beforeEach(function() {
-    dgeni = new Dgeni([testPackage('target-package', true)]);
-    injector = dgeni.configureInjector();
-    targetInlineTagDef = injector.get('targetInlineTagDef');
-  });
-
-
-  it('should filter out content that does not match the targetEnvironments', function() {
-
-    var doc = {};
-
-    var targetEnvironments = injector.get('targetEnvironments');
-    targetEnvironments.addAllowed('js', true);
-    targetEnvironments.addAllowed('es6', true);
-    targetEnvironments.addAllowed('ts', false);
-
-    var result = targetInlineTagDef.handler(doc, 'target', {tag: 'es6 ts', content: 'abc'});
-    expect(result).toEqual('abc');
-
-    result = targetInlineTagDef.handler(doc, 'target', {tag: 'ts', content: 'xyz'});
-    expect(result).toEqual('');
-  });
-
-
-  it('should not filter anything if there are no doc nor global target environments', function() {
-    var doc = {};
-
-    var result = targetInlineTagDef.handler(doc, 'target', {tag: 'es6 ts', content: 'abc'});
-    expect(result).toEqual('abc');
-
-    result = targetInlineTagDef.handler(doc, 'target', {tag: 'ts', content: 'xyz'});
-    expect(result).toEqual('xyz');
-  });
-});
\ No newline at end of file
diff --git a/docs_app/tools/transforms/target-package/services/targetEnvironments.js b/docs_app/tools/transforms/target-package/services/targetEnvironments.js
deleted file mode 100644
index f4236d8d6b..0000000000
--- a/docs_app/tools/transforms/target-package/services/targetEnvironments.js
+++ /dev/null
@@ -1,51 +0,0 @@
-module.exports = function targetEnvironments() {
-  var _targets = Object.create(null);
-  var _activeCount = 0;
-
-  var checkAllowed = function(target) {
-    if (!(target in _targets)) {
-      throw new Error(
-        'Error accessing target "' + target + '". It is not in the list of allowed targets: ' +
-          Object.keys(_targets));
-    }
-  };
-
-  var updateActiveCount = function() {
-    _activeCount = 0;
-    for (let target in _targets) {
-      if (_targets[target]) _activeCount++;
-    }
-  };
-
-  return {
-    addAllowed: function(target, isActive) {
-      _targets[target] = !!isActive;
-      updateActiveCount();
-    },
-    removeAllowed: function(target) {
-      delete _targets[target];
-      updateActiveCount();
-    },
-    activate: function(target) {
-      checkAllowed(target);
-      _targets[target] = true;
-      updateActiveCount();
-    },
-    deactivate: function(target) {
-      checkAllowed(target);
-      _targets[target] = false;
-      updateActiveCount();
-    },
-    isActive: function(target) {
-      checkAllowed(target);
-      return _targets[target];
-    },
-    hasActive: function() { return _activeCount > 0; },
-    someActive: function(targets) {
-      for (var i = 0, ii = targets.length; i < ii; i++) {
-        if (this.isActive(targets[i])) return true;
-      }
-      return false;
-    }
-  };
-};
diff --git a/docs_app/tools/transforms/target-package/services/targetEnvironments.spec.js b/docs_app/tools/transforms/target-package/services/targetEnvironments.spec.js
deleted file mode 100644
index 2f6ec42a5b..0000000000
--- a/docs_app/tools/transforms/target-package/services/targetEnvironments.spec.js
+++ /dev/null
@@ -1,108 +0,0 @@
-var testPackage = require('../../helpers/test-package');
-var Dgeni = require('dgeni');
-
-describe('target inline-tag-def', function() {
-  var dgeni, injector, te;
-
-  beforeEach(function() {
-    dgeni = new Dgeni([testPackage('target-package', true)]);
-    injector = dgeni.configureInjector();
-    te = injector.get('targetEnvironments');
-  });
-
-  describe('addAllowed', function() {
-    it('should store the target and whether it is active', function() {
-      te.addAllowed('a', true);
-      te.addAllowed('b', false);
-      te.addAllowed('c');
-      expect(te.isActive('a')).toBe(true);
-      expect(te.isActive('b')).toBe(false);
-      expect(te.isActive('c')).toBe(false);
-    });
-  });
-
-  describe('removeAllowed', function() {
-    it('should disallow the target', function() {
-      te.addAllowed('a');
-      te.addAllowed('b');
-      te.removeAllowed('b');
-      expect(te.isActive('a')).toBe(false);
-      expect(function() {
-        te.isActive('b');
-      }).toThrowError('Error accessing target "b". It is not in the list of allowed targets: a');
-    });
-  });
-
-  describe('activate', function() {
-    it('should active an already allowed target', function() {
-      te.addAllowed('a', true);
-      te.addAllowed('b', false);
-      te.addAllowed('c');
-
-      te.activate('a');
-      te.activate('b');
-      te.activate('c');
-      expect(te.isActive('a')).toBe(true);
-      expect(te.isActive('b')).toBe(true);
-      expect(te.isActive('c')).toBe(true);
-    });
-  });
-
-  describe('deactivate', function() {
-    it('should deactivate an already allowed target', function() {
-      te.addAllowed('a', true);
-      te.addAllowed('b', false);
-      te.addAllowed('c');
-
-      te.deactivate('a');
-      te.deactivate('b');
-      te.deactivate('c');
-      expect(te.isActive('a')).toBe(false);
-      expect(te.isActive('b')).toBe(false);
-      expect(te.isActive('c')).toBe(false);
-    });
-  });
-
-  describe('isActive', function() {
-    it('should return true if the item is allowed and active', function() {
-      te.addAllowed('a', true);
-      te.addAllowed('b', false);
-
-      expect(te.isActive('a')).toBe(true);
-      expect(te.isActive('b')).toBe(false);
-    });
-  });
-
-  describe('hasActive', function() {
-    it('should return true if there are any active targets', function() {
-      te.addAllowed('a', true);
-      te.addAllowed('b', false);
-      expect(te.hasActive()).toBe(true);
-
-      te.deactivate('a');
-      expect(te.hasActive()).toBe(false);
-
-      te.activate('b');
-      expect(te.hasActive()).toBe(true);
-    });
-  });
-
-  describe('someActive', function() {
-    it('should return true if the array of targets passed are all allowed and at least on is active',
-      function() {
-        te.addAllowed('a', true);
-        te.addAllowed('b', false);
-        te.addAllowed('c');
-
-        expect(te.someActive(['a'])).toBe(true);
-        expect(te.someActive(['b'])).toBe(false);
-        expect(te.someActive(['a', 'b'])).toBe(true);
-        expect(te.someActive(['b', 'c'])).toBe(false);
-        expect(te.someActive([])).toBe(false);
-
-        expect(function() { te.someActive('d'); })
-          .toThrowError(
-            'Error accessing target "d". It is not in the list of allowed targets: a,b,c');
-      });
-  });
-});
diff --git a/docs_app/tools/transforms/templates/api/function.template.html b/docs_app/tools/transforms/templates/api/function.template.html
index c5707f1f2a..25760959d2 100644
--- a/docs_app/tools/transforms/templates/api/function.template.html
+++ b/docs_app/tools/transforms/templates/api/function.template.html
@@ -3,7 +3,7 @@
 {% extends 'export-base.template.html' -%}
 
 {% block overview %}
-{% if doc.overloads.length > 0 and doc.overloads < 3 -%}
+{% if doc.overloads.length > 0 and doc.overloads.length < 3 -%}
   {% for overload in doc.overloads -%}
     {$ memberHelpers.renderOverloadInfo(overload, 'function-overload', doc) $}
     {% if not loop.last %}<hr class="hr-margin fullwidth">{% endif %}
diff --git a/package-lock.json b/package-lock.json
index 02cbdfd928..c2a452e57b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "rxjs",
-  "version": "7.6.0",
+  "version": "7.8.1",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "rxjs",
-      "version": "7.6.0",
+      "version": "7.8.1",
       "license": "Apache-2.0",
       "dependencies": {
         "tslib": "^2.1.0"
diff --git a/package.json b/package.json
index 97084fa311..9e0c07773e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "rxjs",
-  "version": "7.8.1",
+  "version": "7.8.2",
   "description": "Reactive Extensions for modern JavaScript",
   "main": "./dist/cjs/index.js",
   "module": "./dist/esm5/index.js",
diff --git a/spec/Subscriber-spec.ts b/spec/Subscriber-spec.ts
index be229f1ea5..a5a0cc03b7 100644
--- a/spec/Subscriber-spec.ts
+++ b/spec/Subscriber-spec.ts
@@ -9,7 +9,7 @@ describe('SafeSubscriber', () => {
   it('should ignore next messages after unsubscription', () => {
     let times = 0;
 
-    const sub = new SafeSubscriber({
+    const sub = new SafeSubscriber<void>({
       next() { times += 1; }
     });
 
@@ -25,7 +25,7 @@ describe('SafeSubscriber', () => {
     let times = 0;
     let errorCalled = false;
 
-    const sub = new SafeSubscriber({
+    const sub = new SafeSubscriber<void>({
       next() { times += 1; },
       error() { errorCalled = true; }
     });
@@ -44,7 +44,7 @@ describe('SafeSubscriber', () => {
     let times = 0;
     let completeCalled = false;
 
-    const sub = new SafeSubscriber({
+    const sub = new SafeSubscriber<void>({
       next() { times += 1; },
       complete() { completeCalled = true; }
     });
@@ -268,4 +268,4 @@ describe('Subscriber', () => {
   } else {
     console.warn(`No support for FinalizationRegistry in Node ${process.version}`);
   }
-});
\ No newline at end of file
+});
diff --git a/spec/operators/mergeWith-spec.ts b/spec/operators/mergeWith-spec.ts
index 7b7c2538af..1d803de4d1 100644
--- a/spec/operators/mergeWith-spec.ts
+++ b/spec/operators/mergeWith-spec.ts
@@ -46,6 +46,24 @@ describe('merge operator', () => {
     });
   });
 
+  it('should merge a source with a second, when the second is just a plain array', (done) => {
+    const a = of(1, 2, 3);
+    const b = [4, 5, 6, 7, 8];
+    const r = [1, 2, 3, 4, 5, 6, 7, 8];
+
+    a.pipe(mergeWith(b)).subscribe({
+      next: (val) => {
+        expect(val).to.equal(r.shift());
+      },
+      error: () => {
+        done(new Error('should not be called'));
+      },
+      complete: () => {
+        done();
+      },
+    });
+  });
+
   it('should merge cold and cold', () => {
     rxTestScheduler.run(({ cold, expectObservable, expectSubscriptions }) => {
       const e1 = cold(' ---a-----b-----c----|');
diff --git a/spec/schedulers/AnimationFrameScheduler-spec.ts b/spec/schedulers/AnimationFrameScheduler-spec.ts
index eae794b1cb..06de53be7a 100644
--- a/spec/schedulers/AnimationFrameScheduler-spec.ts
+++ b/spec/schedulers/AnimationFrameScheduler-spec.ts
@@ -141,6 +141,52 @@ describe('Scheduler.animationFrame', () => {
     }
   });
 
+  it('should schedule next frame actions from a delayed one', (done) => {
+    animationFrame.schedule(() => {
+      animationFrame.schedule(() => { done(); });
+    }, 1);
+  });
+
+  it('should schedule 2 actions for a subsequent frame', (done) => {
+    let runFirst = false;
+    animationFrame.schedule(() => {
+      animationFrame.schedule(() => { runFirst = true; });
+      animationFrame.schedule(() => {
+        if (runFirst) {
+          done();
+        } else {
+          done(new Error('First action did not run'));
+        }
+      });
+    });
+  });
+
+  it('should handle delayed action without affecting next frame actions', (done) => {
+    let runDelayed = false;
+    let runFirst = false;
+    animationFrame.schedule(() => {
+      animationFrame.schedule(() => {
+        if (!runDelayed) {
+          done(new Error('Delayed action did not run'));
+          return;
+        }
+        runFirst = true;
+      });
+      animationFrame.schedule(() => {
+        if (!runFirst) {
+          done(new Error('First action did not run'));
+        } else {
+          done();
+        }
+      });
+
+      // This action will execute before the next frame because the delay is less than the one of the frame
+      animationFrame.schedule(() => {
+        runDelayed = true;
+      }, 1);
+    });
+  });
+
   it('should not execute rescheduled actions when flushing', (done) => {
     let flushCount = 0;
     let scheduledIndices: number[] = [];
diff --git a/spec/schedulers/AsapScheduler-spec.ts b/spec/schedulers/AsapScheduler-spec.ts
index 5ec0401753..56a2ff7609 100644
--- a/spec/schedulers/AsapScheduler-spec.ts
+++ b/spec/schedulers/AsapScheduler-spec.ts
@@ -66,7 +66,7 @@ describe('Scheduler.asap', () => {
     const sandbox = sinon.createSandbox();
     const fakeTimer = sandbox.useFakeTimers();
     // callThrough is missing from the declarations installed by the typings tool in stable
-    const stubSetInterval = (<any> sandbox.stub(global, 'setInterval')).callThrough();
+    const stubSetInterval = (<any> sandbox.stub(fakeTimer, 'setInterval')).callThrough();
     const period = 50;
     const state = { index: 0, period };
     type State = typeof state;
@@ -92,7 +92,7 @@ describe('Scheduler.asap', () => {
     const sandbox = sinon.createSandbox();
     const fakeTimer = sandbox.useFakeTimers();
     // callThrough is missing from the declarations installed by the typings tool in stable
-    const stubSetInterval = (<any> sandbox.stub(global, 'setInterval')).callThrough();
+    const stubSetInterval = (<any> sandbox.stub(fakeTimer, 'setInterval')).callThrough();
     const period = 50;
     const state = { index: 0, period };
     type State = typeof state;
@@ -148,6 +148,12 @@ describe('Scheduler.asap', () => {
     }, 0, 0);
   });
 
+  it('should schedule asap actions from a delayed one', (done) => {
+    asap.schedule(() => {
+      asap.schedule(() => { done(); });
+    }, 1);
+  });
+
   it('should cancel the setImmediate if all scheduled actions unsubscribe before it executes', (done) => {
     let asapExec1 = false;
     let asapExec2 = false;
diff --git a/src/internal/AsyncSubject.ts b/src/internal/AsyncSubject.ts
index 954cd92aa0..abb086cb38 100644
--- a/src/internal/AsyncSubject.ts
+++ b/src/internal/AsyncSubject.ts
@@ -4,8 +4,6 @@ import { Subscriber } from './Subscriber';
 /**
  * A variant of Subject that only emits a value when it completes. It will emit
  * its latest value to all its observers on completion.
- *
- * @class AsyncSubject<T>
  */
 export class AsyncSubject<T> extends Subject<T> {
   private _value: T | null = null;
diff --git a/src/internal/BehaviorSubject.ts b/src/internal/BehaviorSubject.ts
index 8e561797a8..6540f13efe 100644
--- a/src/internal/BehaviorSubject.ts
+++ b/src/internal/BehaviorSubject.ts
@@ -5,8 +5,6 @@ import { Subscription } from './Subscription';
 /**
  * A variant of Subject that requires an initial value and emits its current
  * value whenever it is subscribed to.
- *
- * @class BehaviorSubject<T>
  */
 export class BehaviorSubject<T> extends Subject<T> {
   constructor(private _value: T) {
diff --git a/src/internal/Notification.ts b/src/internal/Notification.ts
index 4195d049f0..cf344c49a7 100644
--- a/src/internal/Notification.ts
+++ b/src/internal/Notification.ts
@@ -184,10 +184,8 @@ export class Notification<T> {
   /**
    * A shortcut to create a Notification instance of the type `next` from a
    * given value.
-   * @param {T} value The `next` value.
-   * @return {Notification<T>} The "next" Notification representing the
-   * argument.
-   * @nocollapse
+   * @param value The `next` value.
+   * @return The "next" Notification representing the argument.
    * @deprecated It is NOT recommended to create instances of `Notification` directly.
    * Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
    * For example: `{ kind: 'N', value: 1 }`, `{ kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
@@ -200,10 +198,8 @@ export class Notification<T> {
   /**
    * A shortcut to create a Notification instance of the type `error` from a
    * given error.
-   * @param {any} [err] The `error` error.
-   * @return {Notification<T>} The "error" Notification representing the
-   * argument.
-   * @nocollapse
+   * @param err The `error` error.
+   * @return The "error" Notification representing the argument.
    * @deprecated It is NOT recommended to create instances of `Notification` directly.
    * Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
    * For example: `{ kind: 'N', value: 1 }`, `{ kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
@@ -215,8 +211,7 @@ export class Notification<T> {
 
   /**
    * A shortcut to create a Notification instance of the type `complete`.
-   * @return {Notification<any>} The valueless "complete" Notification.
-   * @nocollapse
+   * @return The valueless "complete" Notification.
    * @deprecated It is NOT recommended to create instances of `Notification` directly.
    * Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
    * For example: `{ kind: 'N', value: 1 }`, `{ kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
diff --git a/src/internal/Observable.ts b/src/internal/Observable.ts
index c40a6ded4d..2da026f44d 100644
--- a/src/internal/Observable.ts
+++ b/src/internal/Observable.ts
@@ -11,8 +11,6 @@ import { errorContext } from './util/errorContext';
 /**
  * A representation of any set of values over any amount of time. This is the most basic building block
  * of RxJS.
- *
- * @class Observable<T>
  */
 export class Observable<T> implements Subscribable<T> {
   /**
@@ -26,8 +24,7 @@ export class Observable<T> implements Subscribable<T> {
   operator: Operator<any, T> | undefined;
 
   /**
-   * @constructor
-   * @param {Function} subscribe the function that is called when the Observable is
+   * @param subscribe The function that is called when the Observable is
    * initially subscribed to. This function is given a Subscriber, to which new values
    * can be `next`ed, or an `error` method can be called to raise an error, or
    * `complete` can be called to notify of a successful completion.
@@ -42,11 +39,8 @@ export class Observable<T> implements Subscribable<T> {
   // fight against TypeScript here so Subject can have a different static create signature
   /**
    * Creates a new Observable by calling the Observable constructor
-   * @owner Observable
-   * @method create
-   * @param {Function} subscribe? the subscriber function to be passed to the Observable constructor
-   * @return {Observable} a new observable
-   * @nocollapse
+   * @param subscribe the subscriber function to be passed to the Observable constructor
+   * @return A new observable.
    * @deprecated Use `new Observable()` instead. Will be removed in v8.
    */
   static create: (...args: any[]) => any = <T>(subscribe?: (subscriber: Subscriber<T>) => TeardownLogic) => {
@@ -56,9 +50,8 @@ export class Observable<T> implements Subscribable<T> {
   /**
    * Creates a new Observable, with this Observable instance as the source, and the passed
    * operator defined as the new observable's operator.
-   * @method lift
    * @param operator the operator defining the operation to take on the observable
-   * @return a new observable with the Operator applied
+   * @return A new observable with the Operator applied.
    * @deprecated Internal implementation detail, do not use directly. Will be made internal in v8.
    * If you have implemented an operator using `lift`, it is recommended that you create an
    * operator by simply returning `new Observable()` directly. See "Creating new operators from
@@ -201,14 +194,12 @@ export class Observable<T> implements Subscribable<T> {
    * // 'unsubscribed!' after 2.5s
    * ```
    *
-   * @param {Observer|Function} observerOrNext (optional) Either an observer with methods to be called,
-   * or the first of three possible handlers, which is the handler for each value emitted from the subscribed
-   * Observable.
-   * @param {Function} error (optional) A handler for a terminal event resulting from an error. If no error handler is provided,
+   * @param observerOrNext Either an {@link Observer} with some or all callback methods,
+   * or the `next` handler that is called for each value emitted from the subscribed Observable.
+   * @param error A handler for a terminal event resulting from an error. If no error handler is provided,
    * the error will be thrown asynchronously as unhandled.
-   * @param {Function} complete (optional) A handler for a terminal event resulting from successful completion.
-   * @return {Subscription} a subscription reference to the registered handlers
-   * @method subscribe
+   * @param complete A handler for a terminal event resulting from successful completion.
+   * @return A subscription reference to the registered handlers.
    */
   subscribe(
     observerOrNext?: Partial<Observer<T>> | ((value: T) => void) | null,
@@ -290,9 +281,9 @@ export class Observable<T> implements Subscribable<T> {
    * // 'Total: 6'
    * ```
    *
-   * @param next a handler for each value emitted by the observable
-   * @return a promise that either resolves on observable completion or
-   *  rejects with the handled error
+   * @param next A handler for each value emitted by the observable.
+   * @return A promise that either resolves on observable completion or
+   * rejects with the handled error.
    */
   forEach(next: (value: T) => void): Promise<void>;
 
@@ -336,8 +327,7 @@ export class Observable<T> implements Subscribable<T> {
 
   /**
    * An interop point defined by the es7-observable spec https://github.com/zenparsing/es-observable
-   * @method Symbol.observable
-   * @return {Observable} this instance of the observable
+   * @return This instance of the observable.
    */
   [Symbol_observable]() {
     return this;
@@ -415,9 +405,6 @@ export class Observable<T> implements Subscribable<T> {
 
   /**
    * Used to stitch together functional operators into a chain.
-   * @method pipe
-   * @return {Observable} the Observable result of all of the operators having
-   * been called in the order they were passed in.
    *
    * ## Example
    *
@@ -432,6 +419,9 @@ export class Observable<T> implements Subscribable<T> {
    *   )
    *   .subscribe(x => console.log(x));
    * ```
+   *
+   * @return The Observable result of all the operators having been called
+   * in the order they were passed in.
    */
   pipe(...operations: OperatorFunction<any, any>[]): Observable<any> {
     return pipeFromArray(operations)(this);
@@ -456,7 +446,6 @@ export class Observable<T> implements Subscribable<T> {
    * this situation, look into adding something like {@link timeout}, {@link take},
    * {@link takeWhile}, or {@link takeUntil} amongst others.
    *
-   * @method toPromise
    * @param [promiseCtor] a constructor function used to instantiate
    * the Promise
    * @return A Promise that resolves with the last value emit, or
diff --git a/src/internal/ReplaySubject.ts b/src/internal/ReplaySubject.ts
index a81d7353ac..67394b7c5d 100644
--- a/src/internal/ReplaySubject.ts
+++ b/src/internal/ReplaySubject.ts
@@ -39,9 +39,9 @@ export class ReplaySubject<T> extends Subject<T> {
   private _infiniteTimeWindow = true;
 
   /**
-   * @param bufferSize The size of the buffer to replay on subscription
-   * @param windowTime The amount of time the buffered items will stay buffered
-   * @param timestampProvider An object with a `now()` method that provides the current timestamp. This is used to
+   * @param _bufferSize The size of the buffer to replay on subscription
+   * @param _windowTime The amount of time the buffered items will stay buffered
+   * @param _timestampProvider An object with a `now()` method that provides the current timestamp. This is used to
    * calculate the amount of time something has been buffered.
    */
   constructor(
diff --git a/src/internal/Scheduler.ts b/src/internal/Scheduler.ts
index 7906d22259..0c3d6b65f5 100644
--- a/src/internal/Scheduler.ts
+++ b/src/internal/Scheduler.ts
@@ -17,7 +17,6 @@ import { dateTimestampProvider } from './scheduler/dateTimestampProvider';
  * }
  * ```
  *
- * @class Scheduler
  * @deprecated Scheduler is an internal implementation detail of RxJS, and
  * should not be used directly. Rather, create your own class and implement
  * {@link SchedulerLike}. Will be made internal in v8.
@@ -33,7 +32,7 @@ export class Scheduler implements SchedulerLike {
    * A getter method that returns a number representing the current time
    * (at the time this function was called) according to the scheduler's own
    * internal clock.
-   * @return {number} A number that represents the current time. May or may not
+   * @return A number that represents the current time. May or may not
    * have a relation to wall-clock time. May or may not refer to a time unit
    * (e.g. milliseconds).
    */
@@ -47,14 +46,13 @@ export class Scheduler implements SchedulerLike {
    * The given arguments will be processed an stored as an Action object in a
    * queue of actions.
    *
-   * @param {function(state: ?T): ?Subscription} work A function representing a
-   * task, or some unit of work to be executed by the Scheduler.
-   * @param {number} [delay] Time to wait before executing the work, where the
-   * time unit is implicit and defined by the Scheduler itself.
-   * @param {T} [state] Some contextual data that the `work` function uses when
-   * called by the Scheduler.
-   * @return {Subscription} A subscription in order to be able to unsubscribe
-   * the scheduled work.
+   * @param work A function representing a task, or some unit of work to be
+   * executed by the Scheduler.
+   * @param delay Time to wait before executing the work, where the time unit is
+   * implicit and defined by the Scheduler itself.
+   * @param state Some contextual data that the `work` function uses when called
+   * by the Scheduler.
+   * @return A subscription in order to be able to unsubscribe the scheduled work.
    */
   public schedule<T>(work: (this: SchedulerAction<T>, state?: T) => void, delay: number = 0, state?: T): Subscription {
     return new this.schedulerActionCtor<T>(this, work).schedule(state, delay);
diff --git a/src/internal/Subject.ts b/src/internal/Subject.ts
index d514552919..61ed267658 100644
--- a/src/internal/Subject.ts
+++ b/src/internal/Subject.ts
@@ -31,7 +31,6 @@ export class Subject<T> extends Observable<T> implements SubscriptionLike {
   /**
    * Creates a "subject" by basically gluing an observer to an observable.
    *
-   * @nocollapse
    * @deprecated Recommended you do not use. Will be removed at some point in the future. Plans for replacement still under discussion.
    */
   static create: (...args: any[]) => any = <T>(destination: Observer<T>, source: Observable<T>): AnonymousSubject<T> => {
@@ -148,7 +147,7 @@ export class Subject<T> extends Observable<T> implements SubscriptionLike {
    * Creates a new Observable with this Subject as the source. You can do this
    * to create custom Observer-side logic of the Subject and conceal it from
    * code that uses the Observable.
-   * @return {Observable} Observable that the Subject casts to
+   * @return Observable that this Subject casts to.
    */
   asObservable(): Observable<T> {
     const observable: any = new Observable<T>();
@@ -157,9 +156,6 @@ export class Subject<T> extends Observable<T> implements SubscriptionLike {
   }
 }
 
-/**
- * @class AnonymousSubject<T>
- */
 export class AnonymousSubject<T> extends Subject<T> {
   constructor(
     /** @deprecated Internal implementation detail, do not use directly. Will be made internal in v8. */
diff --git a/src/internal/Subscriber.ts b/src/internal/Subscriber.ts
index e682fe402b..4a96c0e9e8 100644
--- a/src/internal/Subscriber.ts
+++ b/src/internal/Subscriber.ts
@@ -15,8 +15,6 @@ import { captureError } from './util/errorContext';
  * a Subscriber, in order to provide Subscription-like capabilities such as
  * `unsubscribe`. Subscriber is a common type in RxJS, and crucial for
  * implementing operators, but it is rarely used as a public API.
- *
- * @class Subscriber<T>
  */
 export class Subscriber<T> extends Subscription implements Observer<T> {
   /**
@@ -29,7 +27,6 @@ export class Subscriber<T> extends Subscription implements Observer<T> {
    * Observer.
    * @return A Subscriber wrapping the (partially defined)
    * Observer represented by the given arguments.
-   * @nocollapse
    * @deprecated Do not use. Will be removed in v8. There is no replacement for this
    * method, and there is no reason to be creating instances of `Subscriber` directly.
    * If you have a specific use case, please file an issue.
@@ -65,10 +62,9 @@ export class Subscriber<T> extends Subscription implements Observer<T> {
    * The {@link Observer} callback to receive notifications of type `next` from
    * the Observable, with a value. The Observable may call this method 0 or more
    * times.
-   * @param {T} [value] The `next` value.
-   * @return {void}
+   * @param value The `next` value.
    */
-  next(value?: T): void {
+  next(value: T): void {
     if (this.isStopped) {
       handleStoppedNotification(nextNotification(value), this);
     } else {
@@ -80,8 +76,7 @@ export class Subscriber<T> extends Subscription implements Observer<T> {
    * The {@link Observer} callback to receive notifications of type `error` from
    * the Observable, with an attached `Error`. Notifies the Observer that
    * the Observable has experienced an error condition.
-   * @param {any} [err] The `error` exception.
-   * @return {void}
+   * @param err The `error` exception.
    */
   error(err?: any): void {
     if (this.isStopped) {
@@ -96,7 +91,6 @@ export class Subscriber<T> extends Subscription implements Observer<T> {
    * The {@link Observer} callback to receive a valueless notification of type
    * `complete` from the Observable. Notifies the Observer that the Observable
    * has finished sending push-based notifications.
-   * @return {void}
    */
   complete(): void {
     if (this.isStopped) {
@@ -203,7 +197,7 @@ export class SafeSubscriber<T> extends Subscriber<T> {
       // The first argument is a function, not an observer. The next
       // two arguments *could* be observers, or they could be empty.
       partialObserver = {
-        next: (observerOrNext ?? undefined) as (((value: T) => void) | undefined),
+        next: (observerOrNext ?? undefined) as ((value: T) => void) | undefined,
         error: error ?? undefined,
         complete: complete ?? undefined,
       };
@@ -255,8 +249,8 @@ function defaultErrorHandler(err: any) {
 
 /**
  * A handler for notifications that cannot be sent to a stopped subscriber.
- * @param notification The notification being sent
- * @param subscriber The stopped subscriber
+ * @param notification The notification being sent.
+ * @param subscriber The stopped subscriber.
  */
 function handleStoppedNotification(notification: ObservableNotification<any>, subscriber: Subscriber<any>) {
   const { onStoppedNotification } = config;
diff --git a/src/internal/Subscription.ts b/src/internal/Subscription.ts
index ab601315d0..97f7b33842 100644
--- a/src/internal/Subscription.ts
+++ b/src/internal/Subscription.ts
@@ -12,11 +12,8 @@ import { arrRemove } from './util/arrRemove';
  * method, which will attach a child Subscription to the current Subscription.
  * When a Subscription is unsubscribed, all its children (and its grandchildren)
  * will be unsubscribed as well.
- *
- * @class Subscription
  */
 export class Subscription implements SubscriptionLike {
-  /** @nocollapse */
   public static EMPTY = (() => {
     const empty = new Subscription();
     empty.closed = true;
@@ -46,7 +43,6 @@ export class Subscription implements SubscriptionLike {
    * Disposes the resources held by the subscription. May, for instance, cancel
    * an ongoing Observable execution or cancel any other type of work that
    * started when the Subscription was created.
-   * @return {void}
    */
   unsubscribe(): void {
     let errors: any[] | undefined;
diff --git a/src/internal/ajax/errors.ts b/src/internal/ajax/errors.ts
index bb220a2481..36b6dc7ff7 100644
--- a/src/internal/ajax/errors.ts
+++ b/src/internal/ajax/errors.ts
@@ -6,8 +6,6 @@ import { createErrorClass } from '../util/createErrorClass';
  * A normalized AJAX error.
  *
  * @see {@link ajax}
- *
- * @class AjaxError
  */
 export interface AjaxError extends Error {
   /**
@@ -51,7 +49,6 @@ export interface AjaxErrorCtor {
  * is an `instanceof AjaxError`. DO NOT create new instances of `AjaxError` with
  * the constructor.
  *
- * @class AjaxError
  * @see {@link ajax}
  */
 export const AjaxError: AjaxErrorCtor = createErrorClass(
@@ -92,7 +89,6 @@ export interface AjaxTimeoutErrorCtor {
  * `instanceof AjaxTimeoutError`. DO NOT use the constructor to create an instance of
  * this type.
  *
- * @class AjaxTimeoutError
  * @see {@link ajax}
  */
 export const AjaxTimeoutError: AjaxTimeoutErrorCtor = (() => {
diff --git a/src/internal/observable/bindCallback.ts b/src/internal/observable/bindCallback.ts
index f402517e9b..a4bd5740ce 100644
--- a/src/internal/observable/bindCallback.ts
+++ b/src/internal/observable/bindCallback.ts
@@ -71,7 +71,8 @@ export function bindCallback<A extends readonly unknown[], R extends readonly un
  *
  * ## Examples
  *
- * ### Convert jQuery's getJSON to an Observable API
+ * Convert jQuery's getJSON to an Observable API
+ *
  * ```ts
  * import { bindCallback } from 'rxjs';
  * import * as jQuery from 'jquery';
@@ -82,7 +83,8 @@ export function bindCallback<A extends readonly unknown[], R extends readonly un
  * result.subscribe(x => console.log(x), e => console.error(e));
  * ```
  *
- * ### Receive an array of arguments passed to a callback
+ * Receive an array of arguments passed to a callback
+ *
  * ```ts
  * import { bindCallback } from 'rxjs';
  *
@@ -96,7 +98,8 @@ export function bindCallback<A extends readonly unknown[], R extends readonly un
  * });
  * ```
  *
- * ### Compare behaviour with and without async Scheduler
+ * Compare behaviour with and without `asyncScheduler`
+ *
  * ```ts
  * import { bindCallback, asyncScheduler } from 'rxjs';
  *
@@ -117,7 +120,8 @@ export function bindCallback<A extends readonly unknown[], R extends readonly un
  * // I was async!
  * ```
  *
- * ### Use bindCallback on an object method
+ * Use `bindCallback` on an object method
+ *
  * ```ts
  * import { bindCallback } from 'rxjs';
  *
@@ -130,11 +134,11 @@ export function bindCallback<A extends readonly unknown[], R extends readonly un
  * @see {@link bindNodeCallback}
  * @see {@link from}
  *
- * @param {function} func A function with a callback as the last parameter.
- * @param {SchedulerLike} [scheduler] The scheduler on which to schedule the
- * callbacks.
- * @return {function(...params: *): Observable} A function which returns the
- * Observable that delivers the same values the callback would deliver.
+ * @param callbackFunc A function with a callback as the last parameter.
+ * @param resultSelector A mapping function used to transform callback events.
+ * @param scheduler The scheduler on which to schedule the callbacks.
+ * @return A function which returns the Observable that delivers the same
+ * values the callback would deliver.
  */
 export function bindCallback(
   callbackFunc: (...args: [...any[], (...res: any) => void]) => void,
diff --git a/src/internal/observable/bindNodeCallback.ts b/src/internal/observable/bindNodeCallback.ts
index 7c5f060497..8d837225f8 100644
--- a/src/internal/observable/bindNodeCallback.ts
+++ b/src/internal/observable/bindNodeCallback.ts
@@ -74,7 +74,9 @@ export function bindNodeCallback<A extends readonly unknown[], R extends readonl
  * is falsy, it still won't appear in array emitted by Observable.
  *
  * ## Examples
- * ###  Read a file from the filesystem and get the data as an Observable
+ *
+ *  Read a file from the filesystem and get the data as an Observable
+ *
  * ```ts
  * import * as fs from 'fs';
  * const readFileAsObservable = bindNodeCallback(fs.readFile);
@@ -82,7 +84,8 @@ export function bindNodeCallback<A extends readonly unknown[], R extends readonl
  * result.subscribe(x => console.log(x), e => console.error(e));
  * ```
  *
- * ### Use on function calling callback with multiple arguments
+ * Use on function calling callback with multiple arguments
+ *
  * ```ts
  * someFunction((err, a, b) => {
  *   console.log(err); // null
@@ -96,7 +99,8 @@ export function bindNodeCallback<A extends readonly unknown[], R extends readonl
  * });
  * ```
  *
- * ### Use on function calling callback in regular style
+ * Use on function calling callback in regular style
+ *
  * ```ts
  * someFunction(a => {
  *   console.log(a); // 5
@@ -112,12 +116,11 @@ export function bindNodeCallback<A extends readonly unknown[], R extends readonl
  * @see {@link bindCallback}
  * @see {@link from}
  *
- * @param {function} func Function with a Node.js-style callback as the last parameter.
- * @param {SchedulerLike} [scheduler] The scheduler on which to schedule the
- * callbacks.
- * @return {function(...params: *): Observable} A function which returns the
- * Observable that delivers the same values the Node.js callback would
- * deliver.
+ * @param callbackFunc Function with a Node.js-style callback as the last parameter.
+ * @param resultSelector A mapping function used to transform callback events.
+ * @param scheduler The scheduler on which to schedule the callbacks.
+ * @return A function which returns the Observable that delivers the same values the
+ * Node.js callback would deliver.
  */
 export function bindNodeCallback(
   callbackFunc: (...args: [...any[], (err: any, ...res: any) => void]) => void,
diff --git a/src/internal/observable/combineLatest.ts b/src/internal/observable/combineLatest.ts
index 5c807b6f69..9044060faa 100644
--- a/src/internal/observable/combineLatest.ts
+++ b/src/internal/observable/combineLatest.ts
@@ -188,15 +188,11 @@ export function combineLatest<T extends Record<string, ObservableInput<any>>>(
  * @see {@link merge}
  * @see {@link withLatestFrom}
  *
- * @param {ObservableInput} [observables] An array of input Observables to combine with each other.
- * An array of Observables must be given as the first argument.
- * @param {function} [project] An optional function to project the values from
- * the combined latest values into a new value on the output Observable.
- * @param {SchedulerLike} [scheduler=null] The {@link SchedulerLike} to use for subscribing to
- * each input Observable.
- * @return {Observable} An Observable of projected values from the most recent
- * values from each input Observable, or an array of the most recent values from
- * each input Observable.
+ * @param args Any number of `ObservableInput`s provided either as an array or as an object
+ * to combine with each other. If the last parameter is the function, it will be used to project the
+ * values from the combined latest values into a new value on the output Observable.
+ * @return An Observable of projected values from the most recent values from each `ObservableInput`,
+ * or an array of the most recent values from each `ObservableInput`.
  */
 export function combineLatest<O extends ObservableInput<any>, R>(...args: any[]): Observable<R> | Observable<ObservedValueOf<O>[]> {
   const scheduler = popScheduler(args);
diff --git a/src/internal/observable/concat.ts b/src/internal/observable/concat.ts
index 75f9722f02..edbaa31de9 100644
--- a/src/internal/observable/concat.ts
+++ b/src/internal/observable/concat.ts
@@ -108,7 +108,7 @@ export function concat<T extends readonly unknown[]>(
  * @see {@link startWith}
  * @see {@link endWith}
  *
- * @param args Input Observables to concatenate.
+ * @param args `ObservableInput`s to concatenate.
  */
 export function concat(...args: any[]): Observable<unknown> {
   return concatAll()(from(args, popScheduler(args)));
diff --git a/src/internal/observable/defer.ts b/src/internal/observable/defer.ts
index 2e54b37246..2bd3db90bc 100644
--- a/src/internal/observable/defer.ts
+++ b/src/internal/observable/defer.ts
@@ -43,12 +43,11 @@ import { innerFrom } from './innerFrom';
  *
  * @see {@link Observable}
  *
- * @param {function(): ObservableInput} observableFactory The Observable
- * factory function to invoke for each Observer that subscribes to the output
- * Observable. May also return a Promise, which will be converted on the fly
- * to an Observable.
- * @return {Observable} An Observable whose Observers' subscriptions trigger
- * an invocation of the given Observable factory function.
+ * @param observableFactory The Observable factory function to invoke for each
+ * Observer that subscribes to the output Observable. May also return any
+ * `ObservableInput`, which will be converted on the fly to an Observable.
+ * @return An Observable whose Observers' subscriptions trigger an invocation of the
+ * given Observable factory function.
  */
 export function defer<R extends ObservableInput<any>>(observableFactory: () => R): Observable<ObservedValueOf<R>> {
   return new Observable<ObservedValueOf<R>>((subscriber) => {
diff --git a/src/internal/observable/dom/webSocket.ts b/src/internal/observable/dom/webSocket.ts
index d642f0b4b3..b10c5d8d16 100644
--- a/src/internal/observable/dom/webSocket.ts
+++ b/src/internal/observable/dom/webSocket.ts
@@ -153,9 +153,8 @@ import { WebSocketSubject, WebSocketSubjectConfig } from './WebSocketSubject';
  * // socket connection closes.
  * ```
  *
- * @param {string|WebSocketSubjectConfig} urlConfigOrSource The WebSocket endpoint as an url or an object with
- * configuration and additional Observers.
- * @return {WebSocketSubject} Subject which allows to both send and receive messages via WebSocket connection.
+ * @param urlConfigOrSource The WebSocket endpoint as an url or an object with configuration and additional Observers.
+ * @return Subject which allows to both send and receive messages via WebSocket connection.
  */
 export function webSocket<T>(urlConfigOrSource: string | WebSocketSubjectConfig<T>): WebSocketSubject<T> {
   return new WebSocketSubject<T>(urlConfigOrSource);
diff --git a/src/internal/observable/forkJoin.ts b/src/internal/observable/forkJoin.ts
index 21eb3cc319..ec9c418e61 100644
--- a/src/internal/observable/forkJoin.ts
+++ b/src/internal/observable/forkJoin.ts
@@ -137,11 +137,9 @@ export function forkJoin<T extends Record<string, ObservableInput<any>>>(
  * @see {@link combineLatest}
  * @see {@link zip}
  *
- * @param {...ObservableInput} args Any number of Observables provided either as an array or as an arguments
- * passed directly to the operator.
- * @param {function} [project] Function that takes values emitted by input Observables and returns value
- * that will appear in resulting Observable instead of default array.
- * @return {Observable} Observable emitting either an array of last values emitted by passed Observables
+ * @param args Any number of `ObservableInput`s provided either as an array, as an object
+ * or as arguments passed directly to the operator.
+ * @return Observable emitting either an array of last values emitted by passed Observables
  * or value from project function.
  */
 export function forkJoin(...args: any[]): Observable<any> {
diff --git a/src/internal/observable/from.ts b/src/internal/observable/from.ts
index 834bb22852..42e1a42dac 100644
--- a/src/internal/observable/from.ts
+++ b/src/internal/observable/from.ts
@@ -94,10 +94,10 @@ export function from<O extends ObservableInput<any>>(input: O, scheduler: Schedu
  * @see {@link fromEvent}
  * @see {@link fromEventPattern}
  *
- * @param {ObservableInput<T>} A subscription object, a Promise, an Observable-like,
+ * @param input A subscription object, a Promise, an Observable-like,
  * an Array, an iterable, or an array-like object to be converted.
- * @param {SchedulerLike} An optional {@link SchedulerLike} on which to schedule the emission of values.
- * @return {Observable<T>}
+ * @param scheduler An optional {@link SchedulerLike} on which to schedule the emission of values.
+ * @return An Observable converted from {@link ObservableInput}.
  */
 export function from<T>(input: ObservableInput<T>, scheduler?: SchedulerLike): Observable<T> {
   return scheduler ? scheduled(input, scheduler) : innerFrom(input);
diff --git a/src/internal/observable/fromEvent.ts b/src/internal/observable/fromEvent.ts
index e9c7c9230c..ef15431673 100644
--- a/src/internal/observable/fromEvent.ts
+++ b/src/internal/observable/fromEvent.ts
@@ -227,12 +227,15 @@ export function fromEvent<T, R>(
  * @see {@link bindNodeCallback}
  * @see {@link fromEventPattern}
  *
- * @param {FromEventTarget<T>} target The DOM EventTarget, Node.js
- * EventEmitter, JQuery-like event target, NodeList or HTMLCollection to attach the event handler to.
- * @param {string} eventName The event name of interest, being emitted by the
- * `target`.
- * @param {EventListenerOptions} [options] Options to pass through to addEventListener
- * @return {Observable<T>}
+ * @param target The DOM EventTarget, Node.js EventEmitter, JQuery-like event target,
+ * NodeList or HTMLCollection to attach the event handler to.
+ * @param eventName The event name of interest, being emitted by the `target`.
+ * @param options Options to pass through to the underlying `addListener`,
+ * `addEventListener` or `on` functions.
+ * @param resultSelector A mapping function used to transform events. It takes the
+ * arguments from the event handler and should return a single value.
+ * @return An Observable emitting events registered through `target`'s
+ * listener handlers.
  */
 export function fromEvent<T>(
   target: any,
diff --git a/src/internal/observable/fromEventPattern.ts b/src/internal/observable/fromEventPattern.ts
index fee384765f..6e700b1862 100644
--- a/src/internal/observable/fromEventPattern.ts
+++ b/src/internal/observable/fromEventPattern.ts
@@ -125,18 +125,15 @@ export function fromEventPattern<T>(
  * @see {@link bindCallback}
  * @see {@link bindNodeCallback}
  *
- * @param {function(handler: Function): any} addHandler A function that takes
- * a `handler` function as argument and attaches it somehow to the actual
- * source of events.
- * @param {function(handler: Function, token?: any): void} [removeHandler] A function that
- * takes a `handler` function as an argument and removes it from the event source. If `addHandler`
- * returns some kind of token, `removeHandler` function will have it as a second parameter.
- * @param {function(...args: any): T} [project] A function to
- * transform results. It takes the arguments from the event handler and
- * should return a single value.
- * @return {Observable<T>} Observable which, when an event happens, emits first parameter
- * passed to registered event handler. Alternatively it emits whatever project function returns
- * at that moment.
+ * @param addHandler A function that takes a `handler` function as argument and attaches it
+ * somehow to the actual source of events.
+ * @param removeHandler A function that takes a `handler` function as an argument and removes
+ * it from the event source. If `addHandler` returns some kind of token, `removeHandler` function
+ * will have it as a second parameter.
+ * @param resultSelector A function to transform results. It takes the arguments from the event
+ * handler and should return a single value.
+ * @return Observable which, when an event happens, emits first parameter passed to registered
+ * event handler. Alternatively it emits whatever project function returns at that moment.
  */
 export function fromEventPattern<T>(
   addHandler: (handler: NodeEventHandler) => any,
diff --git a/src/internal/observable/generate.ts b/src/internal/observable/generate.ts
index e8af3036fd..0b728bebb0 100644
--- a/src/internal/observable/generate.ts
+++ b/src/internal/observable/generate.ts
@@ -80,13 +80,15 @@ export interface GenerateOptions<T, S> extends GenerateBaseOptions<S> {
  * @see {@link from}
  * @see {@link Observable}
  *
- * @param {S} initialState Initial state.
- * @param {function (state: S): boolean} condition Condition to terminate generation (upon returning false).
- * @param {function (state: S): S} iterate Iteration step function.
- * @param {function (state: S): T} resultSelector Selector function for results produced in the sequence. (deprecated)
- * @param {SchedulerLike} [scheduler] A {@link SchedulerLike} on which to run the generator loop. If not provided, defaults to emit immediately.
- * @returns {Observable<T>} The generated sequence.
- * @deprecated Instead of passing separate arguments, use the options argument. Signatures taking separate arguments will be removed in v8.
+ * @param initialState Initial state.
+ * @param condition Condition to terminate generation (upon returning false).
+ * @param iterate Iteration step function.
+ * @param resultSelector Selector function for results produced in the sequence.
+ * @param scheduler A {@link SchedulerLike} on which to run the generator loop.
+ * If not provided, defaults to emit immediately.
+ * @returns The generated sequence.
+ * @deprecated Instead of passing separate arguments, use the options argument.
+ * Signatures taking separate arguments will be removed in v8.
  */
 export function generate<T, S>(
   initialState: S,
@@ -230,13 +232,14 @@ export function generate<T, S>(
  *
  * @see {@link from}
  *
- * @param {S} initialState Initial state.
- * @param {function (state: S): boolean} condition Condition to terminate generation (upon returning false).
- * @param {function (state: S): S} iterate Iteration step function.
- * @param {function (state: S): T} [resultSelector] Selector function for results produced in the sequence.
- * @param {Scheduler} [scheduler] A {@link Scheduler} on which to run the generator loop. If not provided, defaults to emitting immediately.
- * @return {Observable<T>} The generated sequence.
- * @deprecated Instead of passing separate arguments, use the options argument. Signatures taking separate arguments will be removed in v8.
+ * @param initialState Initial state.
+ * @param condition Condition to terminate generation (upon returning false).
+ * @param iterate Iteration step function.
+ * @param scheduler A {@link Scheduler} on which to run the generator loop. If not
+ * provided, defaults to emitting immediately.
+ * @return The generated sequence.
+ * @deprecated Instead of passing separate arguments, use the options argument.
+ * Signatures taking separate arguments will be removed in v8.
  */
 export function generate<S>(
   initialState: S,
@@ -282,8 +285,8 @@ export function generate<S>(
  * @see {@link from}
  * @see {@link Observable}
  *
- * @param {GenerateBaseOptions<S>} options Object that must contain initialState, iterate and might contain condition and scheduler.
- * @returns {Observable<S>} The generated sequence.
+ * @param options Object that must contain initialState, iterate and might contain condition and scheduler.
+ * @returns The generated sequence.
  */
 export function generate<S>(options: GenerateBaseOptions<S>): Observable<S>;
 
@@ -325,8 +328,8 @@ export function generate<S>(options: GenerateBaseOptions<S>): Observable<S>;
  * @see {@link from}
  * @see {@link Observable}
  *
- * @param {GenerateOptions<T, S>} options Object that must contain initialState, iterate, resultSelector and might contain condition and scheduler.
- * @returns {Observable<T>} The generated sequence.
+ * @param options Object that must contain initialState, iterate, resultSelector and might contain condition and scheduler.
+ * @returns The generated sequence.
  */
 export function generate<T, S>(options: GenerateOptions<T, S>): Observable<T>;
 
diff --git a/src/internal/observable/interval.ts b/src/internal/observable/interval.ts
index fc1b3e0a77..a21809b824 100644
--- a/src/internal/observable/interval.ts
+++ b/src/internal/observable/interval.ts
@@ -41,12 +41,11 @@ import { timer } from './timer';
  * @see {@link timer}
  * @see {@link delay}
  *
- * @param {number} [period=0] The interval size in milliseconds (by default)
- * or the time unit determined by the scheduler's clock.
- * @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for scheduling
- * the emission of values, and providing a notion of "time".
- * @return {Observable} An Observable that emits a sequential number each time
- * interval.
+ * @param period The interval size in milliseconds (by default) or the time unit determined
+ * by the scheduler's clock.
+ * @param scheduler The {@link SchedulerLike} to use for scheduling the emission of values,
+ * and providing a notion of "time".
+ * @return An Observable that emits a sequential number each time interval.
  */
 export function interval(period = 0, scheduler: SchedulerLike = asyncScheduler): Observable<number> {
   if (period < 0) {
diff --git a/src/internal/observable/merge.ts b/src/internal/observable/merge.ts
index 26d35f4f23..de8ac13f3e 100644
--- a/src/internal/observable/merge.ts
+++ b/src/internal/observable/merge.ts
@@ -79,13 +79,11 @@ export function merge<A extends readonly unknown[]>(
  * @see {@link mergeMapTo}
  * @see {@link mergeScan}
  *
- * @param {...ObservableInput} observables Input Observables to merge together.
- * @param {number} [concurrent=Infinity] Maximum number of input
- * Observables being subscribed to concurrently.
- * @param {SchedulerLike} [scheduler=null] The {@link SchedulerLike} to use for managing
- * concurrency of input Observables.
- * @return {Observable} an Observable that emits items that are the result of
- * every input Observable.
+ * @param args `ObservableInput`s to merge together. If the last parameter
+ * is of type number, `merge` will use it to limit number of concurrently
+ * subscribed `ObservableInput`s. If the last parameter is {@link SchedulerLike},
+ * it will be used for scheduling the emission of values.
+ * @return An Observable that emits items that are the result of every input Observable.
  */
 export function merge(...args: (ObservableInput<unknown> | number | SchedulerLike)[]): Observable<unknown> {
   const scheduler = popScheduler(args);
diff --git a/src/internal/observable/of.ts b/src/internal/observable/of.ts
index dc0c918236..a1c9357b17 100644
--- a/src/internal/observable/of.ts
+++ b/src/internal/observable/of.ts
@@ -73,9 +73,9 @@ export function of<A extends readonly unknown[]>(...values: A): Observable<Value
  * @see {@link from}
  * @see {@link range}
  *
- * @param {...T} values A comma separated list of arguments you want to be emitted
- * @return {Observable} An Observable that emits the arguments
- * described above and then completes.
+ * @param args A comma separated list of arguments you want to be emitted.
+ * @return An Observable that synchronously emits the arguments described
+ * above and then immediately completes.
  */
 export function of<T>(...args: Array<T | SchedulerLike>): Observable<T> {
   const scheduler = popScheduler(args);
diff --git a/src/internal/observable/onErrorResumeNext.ts b/src/internal/observable/onErrorResumeNext.ts
index ef62c033a1..d2133eafea 100644
--- a/src/internal/observable/onErrorResumeNext.ts
+++ b/src/internal/observable/onErrorResumeNext.ts
@@ -5,12 +5,9 @@ import { OperatorSubscriber } from '../operators/OperatorSubscriber';
 import { noop } from '../util/noop';
 import { innerFrom } from './innerFrom';
 
-/* tslint:disable:max-line-length */
 export function onErrorResumeNext<A extends readonly unknown[]>(sources: [...ObservableInputTuple<A>]): Observable<A[number]>;
 export function onErrorResumeNext<A extends readonly unknown[]>(...sources: [...ObservableInputTuple<A>]): Observable<A[number]>;
 
-/* tslint:enable:max-line-length */
-
 /**
  * When any of the provided Observable emits a complete or an error notification, it immediately subscribes to the next one
  * that was passed.
@@ -69,8 +66,8 @@ export function onErrorResumeNext<A extends readonly unknown[]>(...sources: [...
  * @see {@link concat}
  * @see {@link catchError}
  *
- * @param {...ObservableInput} sources Observables (or anything that *is* observable) passed either directly or as an array.
- * @return {Observable} An Observable that concatenates all sources, one after the other,
+ * @param sources `ObservableInput`s passed either directly or as an array.
+ * @return An Observable that concatenates all sources, one after the other,
  * ignoring all errors, such that any error causes it to move on to the next source.
  */
 export function onErrorResumeNext<A extends readonly unknown[]>(
diff --git a/src/internal/observable/pairs.ts b/src/internal/observable/pairs.ts
index 4dafb9ffb8..ca4d7f0ac9 100644
--- a/src/internal/observable/pairs.ts
+++ b/src/internal/observable/pairs.ts
@@ -69,12 +69,10 @@ export function pairs(
  * In IE, you will need to polyfill `Object.entries` in order to use this.
  * [MDN has a polyfill here](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries)
  *
- * @param {Object} obj The object to inspect and turn into an
- * Observable sequence.
- * @param {Scheduler} [scheduler] An optional IScheduler to schedule
- * when resulting Observable will emit values.
- * @returns {(Observable<Array<string|T>>)} An observable sequence of
- * [key, value] pairs from the object.
+ * @param obj The object to inspect and turn into an Observable sequence.
+ * @param scheduler An optional IScheduler to schedule when resulting
+ * Observable will emit values.
+ * @returns An observable sequence of [key, value] pairs from the object.
  * @deprecated Use `from(Object.entries(obj))` instead. Will be removed in v8.
  */
 export function pairs(obj: any, scheduler?: SchedulerLike) {
diff --git a/src/internal/observable/partition.ts b/src/internal/observable/partition.ts
index d69db663f5..34a61a14e1 100644
--- a/src/internal/observable/partition.ts
+++ b/src/internal/observable/partition.ts
@@ -64,17 +64,17 @@ export function partition<T>(source: ObservableInput<T>, predicate: (value: T, i
  *
  * @see {@link filter}
  *
- * @param {function(value: T, index: number): boolean} predicate A function that
- * evaluates each value emitted by the source Observable. If it returns `true`,
- * the value is emitted on the first Observable in the returned array, if
- * `false` the value is emitted on the second Observable in the array. The
- * `index` parameter is the number `i` for the i-th source emission that has
- * happened since the subscription, starting from the number `0`.
- * @param {any} [thisArg] An optional argument to determine the value of `this`
- * in the `predicate` function.
- * @return {[Observable<T>, Observable<T>]} An array with two Observables: one
- * with values that passed the predicate, and another with values that did not
- * pass the predicate.
+ * @param source The source `ObservableInput` that will be split into a tuple of
+ * two Observable elements.
+ * @param predicate A function that evaluates each value emitted by the source
+ * Observable. If it returns `true`, the value is emitted on the first Observable
+ * in the returned array, if `false` the value is emitted on the second Observable
+ * in the array. The `index` parameter is the number `i` for the i-th source
+ * emission that has happened since the subscription, starting from the number `0`.
+ * @param thisArg An optional argument to determine the value of `this` in the
+ * `predicate` function.
+ * @return An array with two Observables: one with values that passed the
+ * predicate, and another with values that did not pass the predicate.
  */
 export function partition<T>(
   source: ObservableInput<T>,
diff --git a/src/internal/observable/race.ts b/src/internal/observable/race.ts
index 59b8d0b169..d87293fda3 100644
--- a/src/internal/observable/race.ts
+++ b/src/internal/observable/race.ts
@@ -45,8 +45,8 @@ export function race<T extends readonly unknown[]>(...inputs: [...ObservableInpu
  * // a series of 'fast one'
  * ```
  *
- * @param {...Observables} ...observables sources used to race for which Observable emits first.
- * @return {Observable} an Observable that mirrors the output of the first Observable to emit an item.
+ * @param sources Used to race for which `ObservableInput` emits first.
+ * @return An Observable that mirrors the output of the first Observable to emit an item.
  */
 export function race<T>(...sources: (ObservableInput<T> | ObservableInput<T>[])[]): Observable<any> {
   sources = argsOrArgArray(sources);
diff --git a/src/internal/observable/range.ts b/src/internal/observable/range.ts
index 314ac1bed6..cfc82cff29 100644
--- a/src/internal/observable/range.ts
+++ b/src/internal/observable/range.ts
@@ -46,12 +46,11 @@ export function range(start: number, count: number | undefined, scheduler: Sched
  * @see {@link timer}
  * @see {@link interval}
  *
- * @param {number} [start=0] The value of the first integer in the sequence.
- * @param {number} count The number of sequential integers to generate.
- * @param {SchedulerLike} [scheduler] A {@link SchedulerLike} to use for scheduling
- * the emissions of the notifications.
- * @return {Observable} An Observable of numbers that emits a finite range of
- * sequential integers.
+ * @param start The value of the first integer in the sequence.
+ * @param count The number of sequential integers to generate.
+ * @param scheduler A {@link SchedulerLike} to use for scheduling the emissions
+ * of the notifications.
+ * @return An Observable of numbers that emits a finite range of sequential integers.
  */
 export function range(start: number, count?: number, scheduler?: SchedulerLike): Observable<number> {
   if (count == null) {
diff --git a/src/internal/observable/using.ts b/src/internal/observable/using.ts
index 437fed9c47..e95b1f062b 100644
--- a/src/internal/observable/using.ts
+++ b/src/internal/observable/using.ts
@@ -24,11 +24,9 @@ import { EMPTY } from './empty';
  *
  * @see {@link defer}
  *
- * @param {function(): ISubscription} resourceFactory A function which creates any resource object
- * that implements `unsubscribe` method.
- * @param {function(resource: ISubscription): Observable<T>} observableFactory A function which
- * creates an Observable, that can use injected resource object.
- * @return {Observable<T>} An Observable that behaves the same as Observable returned by `observableFactory`, but
+ * @param resourceFactory A function which creates any resource object that implements `unsubscribe` method.
+ * @param observableFactory A function which creates an Observable, that can use injected resource object.
+ * @return An Observable that behaves the same as Observable returned by `observableFactory`, but
  * which - when completed, errored or unsubscribed - will also call `unsubscribe` on created resource object.
  */
 export function using<T extends ObservableInput<any>>(
diff --git a/src/internal/observable/zip.ts b/src/internal/observable/zip.ts
index e7c5849801..d6d2adf56a 100644
--- a/src/internal/observable/zip.ts
+++ b/src/internal/observable/zip.ts
@@ -45,8 +45,10 @@ export function zip<A extends readonly unknown[], R>(
  * // { age: 29, name: 'Beer', isDev: false }
  * ```
  *
- * @param sources
- * @return {Observable<R>}
+ * @param args Any number of `ObservableInput`s provided either as an array or as an object
+ * to combine with each other.
+ * @return An Observable of array values of the values emitted at the same index from each
+ * individual `ObservableInput`.
  */
 export function zip(...args: unknown[]): Observable<unknown> {
   const resultSelector = popResultSelector(args);
diff --git a/src/internal/operators/auditTime.ts b/src/internal/operators/auditTime.ts
index af83889db9..c2beddf4a9 100644
--- a/src/internal/operators/auditTime.ts
+++ b/src/internal/operators/auditTime.ts
@@ -42,11 +42,11 @@ import { MonoTypeOperatorFunction, SchedulerLike } from '../types';
  * @see {@link sampleTime}
  * @see {@link throttleTime}
  *
- * @param {number} duration Time to wait before emitting the most recent source
- * value, measured in milliseconds or the time unit determined internally
- * by the optional `scheduler`.
- * @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for
- * managing the timers that handle the rate-limiting behavior.
+ * @param duration Time to wait before emitting the most recent source value,
+ * measured in milliseconds or the time unit determined internally by the
+ * optional `scheduler`.
+ * @param scheduler The {@link SchedulerLike} to use for managing the timers
+ * that handle the rate-limiting behavior.
  * @return A function that returns an Observable that performs rate-limiting of
  * emissions from the source Observable.
  */
diff --git a/src/internal/operators/bufferCount.ts b/src/internal/operators/bufferCount.ts
index 4983fec877..1d82d2c213 100644
--- a/src/internal/operators/bufferCount.ts
+++ b/src/internal/operators/bufferCount.ts
@@ -47,8 +47,8 @@ import { arrRemove } from '../util/arrRemove';
  * @see {@link pairwise}
  * @see {@link windowCount}
  *
- * @param {number} bufferSize The maximum size of the buffer emitted.
- * @param {number} [startBufferEvery] Interval at which to start a new buffer.
+ * @param bufferSize The maximum size of the buffer emitted.
+ * @param startBufferEvery Interval at which to start a new buffer.
  * For example if `startBufferEvery` is `2`, then a new buffer will be started
  * on every other value from the source. A new buffer is started at the
  * beginning of the source by default.
diff --git a/src/internal/operators/bufferTime.ts b/src/internal/operators/bufferTime.ts
index 3e547b7324..43a7b13669 100644
--- a/src/internal/operators/bufferTime.ts
+++ b/src/internal/operators/bufferTime.ts
@@ -7,7 +7,6 @@ import { asyncScheduler } from '../scheduler/async';
 import { popScheduler } from '../util/args';
 import { executeSchedule } from '../util/executeSchedule';
 
-/* tslint:disable:max-line-length */
 export function bufferTime<T>(bufferTimeSpan: number, scheduler?: SchedulerLike): OperatorFunction<T, T[]>;
 export function bufferTime<T>(
   bufferTimeSpan: number,
@@ -20,7 +19,6 @@ export function bufferTime<T>(
   maxBufferSize: number,
   scheduler?: SchedulerLike
 ): OperatorFunction<T, T[]>;
-/* tslint:enable:max-line-length */
 
 /**
  * Buffers the source Observable values for a specific time period.
@@ -67,12 +65,11 @@ export function bufferTime<T>(
  * @see {@link bufferWhen}
  * @see {@link windowTime}
  *
- * @param {number} bufferTimeSpan The amount of time to fill each buffer array.
- * @param {number} [bufferCreationInterval] The interval at which to start new
- * buffers.
- * @param {number} [maxBufferSize] The maximum buffer size.
- * @param {SchedulerLike} [scheduler=async] The scheduler on which to schedule the
- * intervals that determine buffer boundaries.
+ * @param bufferTimeSpan The amount of time to fill each buffer array.
+ * @param otherArgs Other configuration arguments such as:
+ * - `bufferCreationInterval` - the interval at which to start new buffers;
+ * - `maxBufferSize` - the maximum buffer size;
+ * - `scheduler` - the scheduler on which to schedule the intervals that determine buffer boundaries.
  * @return A function that returns an Observable of arrays of buffered values.
  */
 export function bufferTime<T>(bufferTimeSpan: number, ...otherArgs: any[]): OperatorFunction<T, T[]> {
diff --git a/src/internal/operators/bufferWhen.ts b/src/internal/operators/bufferWhen.ts
index 00e8c13544..ee644020f1 100644
--- a/src/internal/operators/bufferWhen.ts
+++ b/src/internal/operators/bufferWhen.ts
@@ -39,8 +39,8 @@ import { innerFrom } from '../observable/innerFrom';
  * @see {@link bufferToggle}
  * @see {@link windowWhen}
  *
- * @param {function(): Observable} closingSelector A function that takes no
- * arguments and returns an Observable that signals buffer closure.
+ * @param closingSelector A function that takes no arguments and returns an
+ * Observable that signals buffer closure.
  * @return A function that returns an Observable of arrays of buffered values.
  */
 export function bufferWhen<T>(closingSelector: () => ObservableInput<any>): OperatorFunction<T, T[]> {
diff --git a/src/internal/operators/catchError.ts b/src/internal/operators/catchError.ts
index 39eeb98acd..0e2fc6ddcd 100644
--- a/src/internal/operators/catchError.ts
+++ b/src/internal/operators/catchError.ts
@@ -6,11 +6,9 @@ import { innerFrom } from '../observable/innerFrom';
 import { createOperatorSubscriber } from './OperatorSubscriber';
 import { operate } from '../util/lift';
 
-/* tslint:disable:max-line-length */
 export function catchError<T, O extends ObservableInput<any>>(
   selector: (err: any, caught: Observable<T>) => O
 ): OperatorFunction<T, T | ObservedValueOf<O>>;
-/* tslint:enable:max-line-length */
 
 /**
  * Catches errors on the observable to be handled by returning a new observable or throwing an error.
@@ -98,9 +96,9 @@ export function catchError<T, O extends ObservableInput<any>>(
  * @see {@link retry }
  * @see {@link retryWhen}
  *
- * @param {function} selector a function that takes as arguments `err`, which is the error, and `caught`, which
- * is the source observable, in case you'd like to "retry" that observable by returning it again. Whatever observable
- * is returned by the `selector` will be used to continue the observable chain.
+ * @param selector A function that takes as arguments `err`, which is the error, and `caught`, which
+ * is the source observable, in case you'd like to "retry" that observable by returning it again.
+ * Whatever observable is returned by the `selector` will be used to continue the observable chain.
  * @return A function that returns an Observable that originates from either
  * the source or the Observable returned by the `selector` function.
  */
diff --git a/src/internal/operators/concatMap.ts b/src/internal/operators/concatMap.ts
index 21bbf42431..1a6dc67104 100644
--- a/src/internal/operators/concatMap.ts
+++ b/src/internal/operators/concatMap.ts
@@ -68,9 +68,8 @@ export function concatMap<T, R, O extends ObservableInput<any>>(
  * @see {@link mergeMap}
  * @see {@link switchMap}
  *
- * @param {function(value: T, ?index: number): ObservableInput} project A function
- * that, when applied to an item emitted by the source Observable, returns an
- * Observable.
+ * @param project A function that, when applied to an item emitted by the source
+ * Observable, returns an Observable.
  * @return A function that returns an Observable that emits the result of
  * applying the projection function (and the optional deprecated
  * `resultSelector`) to each item emitted by the source Observable and taking
diff --git a/src/internal/operators/concatMapTo.ts b/src/internal/operators/concatMapTo.ts
index 00798c67c1..9c04b8e200 100644
--- a/src/internal/operators/concatMapTo.ts
+++ b/src/internal/operators/concatMapTo.ts
@@ -64,8 +64,8 @@ export function concatMapTo<T, R, O extends ObservableInput<unknown>>(
  * @see {@link mergeMapTo}
  * @see {@link switchMapTo}
  *
- * @param {ObservableInput} innerObservable An Observable to replace each value from
- * the source Observable.
+ * @param innerObservable An `ObservableInput` to replace each value from the
+ * source Observable.
  * @return A function that returns an Observable of values merged together by
  * joining the passed Observable with itself, one after the other, for each
  * value emitted from the source.
diff --git a/src/internal/operators/debounceTime.ts b/src/internal/operators/debounceTime.ts
index 1bbbe4dbc2..0992bce226 100644
--- a/src/internal/operators/debounceTime.ts
+++ b/src/internal/operators/debounceTime.ts
@@ -51,12 +51,11 @@ import { createOperatorSubscriber } from './OperatorSubscriber';
  * @see {@link throttle}
  * @see {@link throttleTime}
  *
- * @param {number} dueTime The timeout duration in milliseconds (or the time
- * unit determined internally by the optional `scheduler`) for the window of
- * time required to wait for emission silence before emitting the most recent
- * source value.
- * @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for
- * managing the timers that handle the timeout for each value.
+ * @param dueTime The timeout duration in milliseconds (or the time unit determined
+ * internally by the optional `scheduler`) for the window of time required to wait
+ * for emission silence before emitting the most recent source value.
+ * @param scheduler The {@link SchedulerLike} to use for managing the timers that
+ * handle the timeout for each value.
  * @return A function that returns an Observable that delays the emissions of
  * the source Observable by the specified `dueTime`, and may drop some values
  * if they occur too frequently.
diff --git a/src/internal/operators/delay.ts b/src/internal/operators/delay.ts
index 64dd894b29..47fae49869 100644
--- a/src/internal/operators/delay.ts
+++ b/src/internal/operators/delay.ts
@@ -52,10 +52,10 @@ import { timer } from '../observable/timer';
  * @see {@link audit}
  * @see {@link auditTime}
  *
- * @param {number|Date} due The delay duration in milliseconds (a `number`) or
- * a `Date` until which the emission of the source items is delayed.
- * @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for
- * managing the timers that handle the time-shift for each item.
+ * @param due The delay duration in milliseconds (a `number`) or a `Date` until
+ * which the emission of the source items is delayed.
+ * @param scheduler The {@link SchedulerLike} to use for managing the timers
+ * that handle the time-shift for each item.
  * @return A function that returns an Observable that delays the emissions of
  * the source Observable by the specified timeout or Date.
  */
diff --git a/src/internal/operators/distinctUntilKeyChanged.ts b/src/internal/operators/distinctUntilKeyChanged.ts
index 0f67082601..b7c45936e5 100644
--- a/src/internal/operators/distinctUntilKeyChanged.ts
+++ b/src/internal/operators/distinctUntilKeyChanged.ts
@@ -1,16 +1,16 @@
 import { distinctUntilChanged } from './distinctUntilChanged';
 import { MonoTypeOperatorFunction } from '../types';
 
-/* tslint:disable:max-line-length */
 export function distinctUntilKeyChanged<T>(key: keyof T): MonoTypeOperatorFunction<T>;
 export function distinctUntilKeyChanged<T, K extends keyof T>(key: K, compare: (x: T[K], y: T[K]) => boolean): MonoTypeOperatorFunction<T>;
-/* tslint:enable:max-line-length */
 
 /**
- * Returns an Observable that emits all items emitted by the source Observable that are distinct by comparison from the previous item,
- * using a property accessed by using the key provided to check if the two items are distinct.
+ * Returns an Observable that emits all items emitted by the source Observable that
+ * are distinct by comparison from the previous item, using a property accessed by
+ * using the key provided to check if the two items are distinct.
  *
- * If a comparator function is provided, then it will be called for each item to test for whether or not that value should be emitted.
+ * If a comparator function is provided, then it will be called for each item to
+ * test for whether that value should be emitted or not.
  *
  * If a comparator function is not provided, an equality check is used by default.
  *
@@ -61,11 +61,15 @@ export function distinctUntilKeyChanged<T, K extends keyof T>(key: K, compare: (
  * @see {@link distinct}
  * @see {@link distinctUntilChanged}
  *
- * @param {string} key String key for object property lookup on each item.
- * @param {function} [compare] Optional comparison function called to test if an item is distinct from the previous item in the source.
- * @return A function that returns an Observable that emits items from the
- * source Observable with distinct values based on the key specified.
+ * @param key String key for object property lookup on each item.
+ * @param compare Optional comparison function called to test if an item is distinct
+ * from the previous item in the source.
+ * @return A function that returns an Observable that emits items from the source
+ * Observable with distinct values based on the key specified.
  */
-export function distinctUntilKeyChanged<T, K extends keyof T>(key: K, compare?: (x: T[K], y: T[K]) => boolean): MonoTypeOperatorFunction<T> {
-  return distinctUntilChanged((x: T, y: T) => compare ? compare(x[key], y[key]) : x[key] === y[key]);
+export function distinctUntilKeyChanged<T, K extends keyof T>(
+  key: K,
+  compare?: (x: T[K], y: T[K]) => boolean
+): MonoTypeOperatorFunction<T> {
+  return distinctUntilChanged((x: T, y: T) => (compare ? compare(x[key], y[key]) : x[key] === y[key]));
 }
diff --git a/src/internal/operators/elementAt.ts b/src/internal/operators/elementAt.ts
index 6a817fc5dd..47a1d34b1e 100644
--- a/src/internal/operators/elementAt.ts
+++ b/src/internal/operators/elementAt.ts
@@ -44,12 +44,12 @@ import { take } from './take';
  * @see {@link take}
  *
  * @throws {ArgumentOutOfRangeError} When using `elementAt(i)`, it delivers an
- * ArgumentOutOfRangeError to the Observer's `error` callback if `i < 0` or the
+ * `ArgumentOutOfRangeError` to the Observer's `error` callback if `i < 0` or the
  * Observable has completed before emitting the i-th `next` notification.
  *
- * @param {number} index Is the number `i` for the i-th source emission that has
- * happened since the subscription, starting from the number `0`.
- * @param {T} [defaultValue] The default value returned for missing indices.
+ * @param index Is the number `i` for the i-th source emission that has happened
+ * since the subscription, starting from the number `0`.
+ * @param defaultValue The default value returned for missing indices.
  * @return A function that returns an Observable that emits a single item, if
  * it is found. Otherwise, it will emit the default value if given. If not, it
  * emits an error.
diff --git a/src/internal/operators/every.ts b/src/internal/operators/every.ts
index be3d9ea5af..a6a86bfd8b 100644
--- a/src/internal/operators/every.ts
+++ b/src/internal/operators/every.ts
@@ -36,8 +36,8 @@ export function every<T>(predicate: (value: T, index: number, source: Observable
  *   .subscribe(x => console.log(x)); // -> false
  * ```
  *
- * @param {function} predicate A function for determining if an item meets a specified condition.
- * @param {any} [thisArg] Optional object to use for `this` in the callback.
+ * @param predicate A function for determining if an item meets a specified condition.
+ * @param thisArg Optional object to use for `this` in the callback.
  * @return A function that returns an Observable of booleans that determines if
  * all items of the source Observable meet the condition specified.
  */
diff --git a/src/internal/operators/exhaustMap.ts b/src/internal/operators/exhaustMap.ts
index 69bc72805a..bf666830ab 100644
--- a/src/internal/operators/exhaustMap.ts
+++ b/src/internal/operators/exhaustMap.ts
@@ -59,9 +59,8 @@ export function exhaustMap<T, I, R>(
  * @see {@link mergeMap}
  * @see {@link switchMap}
  *
- * @param {function(value: T, ?index: number): ObservableInput} project A function
- * that, when applied to an item emitted by the source Observable, returns an
- * Observable.
+ * @param project A function that, when applied to an item emitted by the source
+ * Observable, returns an Observable.
  * @return A function that returns an Observable containing projected
  * Observables of each item of the source, ignoring projected Observables that
  * start before their preceding Observable has completed.
diff --git a/src/internal/operators/expand.ts b/src/internal/operators/expand.ts
index 84b7e347a6..481a373de1 100644
--- a/src/internal/operators/expand.ts
+++ b/src/internal/operators/expand.ts
@@ -59,12 +59,11 @@ export function expand<T, O extends ObservableInput<unknown>>(
  * @see {@link mergeMap}
  * @see {@link mergeScan}
  *
- * @param {function(value: T, index: number) => Observable} project A function
- * that, when applied to an item emitted by the source or the output Observable,
- * returns an Observable.
- * @param {number} [concurrent=Infinity] Maximum number of input
- * Observables being subscribed to concurrently.
- * @param {SchedulerLike} [scheduler=null] The {@link SchedulerLike} to use for subscribing to
+ * @param project A function that, when applied to an item emitted by the source
+ * or the output Observable, returns an Observable.
+ * @param concurrent Maximum number of input Observables being subscribed to
+ * concurrently.
+ * @param scheduler The {@link SchedulerLike} to use for subscribing to
  * each projected inner Observable.
  * @return A function that returns an Observable that emits the source values
  * and also result of applying the projection function to each value emitted on
diff --git a/src/internal/operators/finalize.ts b/src/internal/operators/finalize.ts
index 7ab08b239c..12821fd23b 100644
--- a/src/internal/operators/finalize.ts
+++ b/src/internal/operators/finalize.ts
@@ -58,7 +58,7 @@ import { operate } from '../util/lift';
  * // '[finalize] Called'
  * ```
  *
- * @param {function} callback Function to be called when source terminates.
+ * @param callback Function to be called when source terminates.
  * @return A function that returns an Observable that mirrors the source, but
  * will call the specified function on termination.
  */
diff --git a/src/internal/operators/find.ts b/src/internal/operators/find.ts
index d91a3d8217..0697abf552 100644
--- a/src/internal/operators/find.ts
+++ b/src/internal/operators/find.ts
@@ -55,10 +55,9 @@ export function find<T>(predicate: (value: T, index: number, source: Observable<
  * @see {@link findIndex}
  * @see {@link take}
  *
- * @param {function(value: T, index: number, source: Observable<T>): boolean} predicate
- * A function called with each item to test for condition matching.
- * @param {any} [thisArg] An optional argument to determine the value of `this`
- * in the `predicate` function.
+ * @param predicate A function called with each item to test for condition matching.
+ * @param thisArg An optional argument to determine the value of `this` in the
+ * `predicate` function.
  * @return A function that returns an Observable that emits the first item that
  * matches the condition.
  */
diff --git a/src/internal/operators/findIndex.ts b/src/internal/operators/findIndex.ts
index 7a9d943cbc..e1ef7574f2 100644
--- a/src/internal/operators/findIndex.ts
+++ b/src/internal/operators/findIndex.ts
@@ -49,10 +49,9 @@ export function findIndex<T>(predicate: (value: T, index: number, source: Observ
  * @see {@link first}
  * @see {@link take}
  *
- * @param {function(value: T, index: number, source: Observable<T>): boolean} predicate
- * A function called with each item to test for condition matching.
- * @param {any} [thisArg] An optional argument to determine the value of `this`
- * in the `predicate` function.
+ * @param predicate A function called with each item to test for condition matching.
+ * @param thisArg An optional argument to determine the value of `this` in the
+ * `predicate` function.
  * @return A function that returns an Observable that emits the index of the
  * first item that matches the condition.
  */
diff --git a/src/internal/operators/first.ts b/src/internal/operators/first.ts
index b3ca1f8e46..337aa59b04 100644
--- a/src/internal/operators/first.ts
+++ b/src/internal/operators/first.ts
@@ -34,8 +34,8 @@ export function first<T, D = T>(
  *
  * If called with no arguments, `first` emits the first value of the source
  * Observable, then completes. If called with a `predicate` function, `first`
- * emits the first value of the source that matches the specified condition. Throws an error if
- * `defaultValue` was not provided and a matching element is not found.
+ * emits the first value of the source that matches the specified condition. Emits an error
+ * notification if `defaultValue` was not provided and a matching element is not found.
  *
  * ## Examples
  *
@@ -66,15 +66,16 @@ export function first<T, D = T>(
  * @see {@link filter}
  * @see {@link find}
  * @see {@link take}
+ * @see {@link last}
  *
- * @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
+ * @throws {EmptyError} Delivers an `EmptyError` to the Observer's `error`
  * callback if the Observable completes before any `next` notification was sent.
- * This is how `first()` is different from {@link take}(1) which completes instead.
+ * This is how `first()` is different from `take(1)` which completes instead.
  *
- * @param {function(value: T, index: number, source: Observable<T>): boolean} [predicate]
- * An optional function called with each item to test for condition matching.
- * @param {D} [defaultValue] The default value emitted in case no valid value
- * was found on the source.
+ * @param predicate An optional function called with each item to test for condition
+ * matching.
+ * @param defaultValue The default value emitted in case no valid value was found on
+ * the source.
  * @return A function that returns an Observable that emits the first item that
  * matches the condition.
  */
diff --git a/src/internal/operators/last.ts b/src/internal/operators/last.ts
index a046922f87..698ce2321e 100644
--- a/src/internal/operators/last.ts
+++ b/src/internal/operators/last.ts
@@ -27,9 +27,9 @@ export function last<T, D = T>(
  *
  * ![](last.png)
  *
- * It will throw an error if the source completes without notification or one that matches the predicate. It
- * returns the last value or if a predicate is provided last value that matches the predicate. It returns the
- * given default value if no notification is emitted or matches the predicate.
+ * It will emit an error notification if the source completes without notification or one that matches
+ * the predicate. It returns the last value or if a predicate is provided last value that matches the
+ * predicate. It returns the given default value if no notification is emitted or matches the predicate.
  *
  * ## Examples
  *
@@ -65,16 +65,17 @@ export function last<T, D = T>(
  * @see {@link skipUntil}
  * @see {@link skipLast}
  * @see {@link skipWhile}
+ * @see {@link first}
  *
- * @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
+ * @throws {EmptyError} Delivers an `EmptyError` to the Observer's `error`
  * callback if the Observable completes before any `next` notification was sent.
- * @param {function} [predicate] - The condition any source emitted item has to satisfy.
- * @param {any} [defaultValue] - An optional default value to provide if last
- * predicate isn't met or no values were emitted.
+ *
+ * @param predicate The condition any source emitted item has to satisfy.
+ * @param defaultValue An optional default value to provide if last `predicate`
+ * isn't met or no values were emitted.
  * @return A function that returns an Observable that emits only the last item
- * satisfying the given condition from the source, or a NoSuchElementException
- * if no such items are emitted.
- * @throws - Throws if no items that match the predicate are emitted by the source Observable.
+ * satisfying the given condition from the source, or an error notification
+ * with an `EmptyError` object if no such items are emitted.
  */
 export function last<T, D>(
   predicate?: ((value: T, index: number, source: Observable<T>) => boolean) | null,
diff --git a/src/internal/operators/map.ts b/src/internal/operators/map.ts
index 35b548f786..fa7305daf1 100644
--- a/src/internal/operators/map.ts
+++ b/src/internal/operators/map.ts
@@ -36,11 +36,10 @@ export function map<T, R, A>(project: (this: A, value: T, index: number) => R, t
  * @see {@link mapTo}
  * @see {@link pluck}
  *
- * @param {function(value: T, index: number): R} project The function to apply
- * to each `value` emitted by the source Observable. The `index` parameter is
- * the number `i` for the i-th emission that has happened since the
- * subscription, starting from the number `0`.
- * @param {any} [thisArg] An optional argument to define what `this` is in the
+ * @param project The function to apply to each `value` emitted by the source
+ * Observable. The `index` parameter is the number `i` for the i-th emission
+ * that has happened since the subscription, starting from the number `0`.
+ * @param thisArg An optional argument to define what `this` is in the
  * `project` function.
  * @return A function that returns an Observable that emits the values from the
  * source Observable transformed by the given `project` function.
diff --git a/src/internal/operators/max.ts b/src/internal/operators/max.ts
index b3c5fcbc77..8c2f5d035d 100644
--- a/src/internal/operators/max.ts
+++ b/src/internal/operators/max.ts
@@ -3,8 +3,9 @@ import { MonoTypeOperatorFunction } from '../types';
 import { isFunction } from '../util/isFunction';
 
 /**
- * The Max operator operates on an Observable that emits numbers (or items that can be compared with a provided function),
- * and when source Observable completes it emits a single item: the item with the largest value.
+ * The `max` operator operates on an Observable that emits numbers (or items that
+ * can be compared with a provided function), and when source Observable completes
+ * it emits a single item: the item with the largest value.
  *
  * ![](max.png)
  *
@@ -43,8 +44,8 @@ import { isFunction } from '../util/isFunction';
  *
  * @see {@link min}
  *
- * @param {Function} [comparer] - Optional comparer function that it will use instead of its default to compare the
- * value of two items.
+ * @param comparer Optional comparer function that it will use instead of its
+ * default to compare the value of two items.
  * @return A function that returns an Observable that emits item with the
  * largest value.
  */
diff --git a/src/internal/operators/merge.ts b/src/internal/operators/merge.ts
index d7cae4e3c0..73fff7dd36 100644
--- a/src/internal/operators/merge.ts
+++ b/src/internal/operators/merge.ts
@@ -1,6 +1,5 @@
 import { ObservableInput, ObservableInputTuple, OperatorFunction, SchedulerLike } from '../types';
 import { operate } from '../util/lift';
-import { argsOrArgArray } from '../util/argsOrArgArray';
 import { mergeAll } from './mergeAll';
 import { popNumber, popScheduler } from '../util/args';
 import { from } from '../observable/from';
@@ -23,7 +22,6 @@ export function merge<T, A extends readonly unknown[]>(
 export function merge<T>(...args: unknown[]): OperatorFunction<T, unknown> {
   const scheduler = popScheduler(args);
   const concurrent = popNumber(args, Infinity);
-  args = argsOrArgArray(args);
 
   return operate((source, subscriber) => {
     mergeAll(concurrent)(from([source, ...(args as ObservableInput<T>[])], scheduler)).subscribe(subscriber);
diff --git a/src/internal/operators/mergeAll.ts b/src/internal/operators/mergeAll.ts
index 9183badacb..51f28fddf7 100644
--- a/src/internal/operators/mergeAll.ts
+++ b/src/internal/operators/mergeAll.ts
@@ -56,8 +56,8 @@ import { OperatorFunction, ObservableInput, ObservedValueOf } from '../types';
  * @see {@link switchMap}
  * @see {@link zipAll}
  *
- * @param {number} [concurrent=Infinity] Maximum number of inner
- * Observables being subscribed to concurrently.
+ * @param concurrent Maximum number of inner Observables being subscribed to
+ * concurrently.
  * @return A function that returns an Observable that emits values coming from
  * all the inner Observables emitted by the source Observable.
  */
diff --git a/src/internal/operators/mergeMap.ts b/src/internal/operators/mergeMap.ts
index 6a8807618f..5b698ea484 100644
--- a/src/internal/operators/mergeMap.ts
+++ b/src/internal/operators/mergeMap.ts
@@ -70,11 +70,9 @@ export function mergeMap<T, R, O extends ObservableInput<any>>(
  * @see {@link mergeScan}
  * @see {@link switchMap}
  *
- * @param {function(value: T, ?index: number): ObservableInput} project A function
- * that, when applied to an item emitted by the source Observable, returns an
- * Observable.
- * @param {number} [concurrent=Infinity] Maximum number of input
- * Observables being subscribed to concurrently.
+ * @param project A function that, when applied to an item emitted by the source
+ * Observable, returns an Observable.
+ * @param concurrent Maximum number of `ObservableInput`s being subscribed to concurrently.
  * @return A function that returns an Observable that emits the result of
  * applying the projection function (and the optional deprecated
  * `resultSelector`) to each item emitted by the source Observable and merging
diff --git a/src/internal/operators/mergeMapTo.ts b/src/internal/operators/mergeMapTo.ts
index b457401978..bcc4654608 100644
--- a/src/internal/operators/mergeMapTo.ts
+++ b/src/internal/operators/mergeMapTo.ts
@@ -51,10 +51,10 @@ export function mergeMapTo<T, R, O extends ObservableInput<unknown>>(
  * @see {@link mergeScan}
  * @see {@link switchMapTo}
  *
- * @param {ObservableInput} innerObservable An Observable to replace each value from
- * the source Observable.
- * @param {number} [concurrent=Infinity] Maximum number of input
- * Observables being subscribed to concurrently.
+ * @param innerObservable An `ObservableInput` to replace each value from the
+ * source Observable.
+ * @param concurrent Maximum number of input Observables being subscribed to
+ * concurrently.
  * @return A function that returns an Observable that emits items from the
  * given `innerObservable`.
  * @deprecated Will be removed in v9. Use {@link mergeMap} instead: `mergeMap(() => result)`
diff --git a/src/internal/operators/mergeScan.ts b/src/internal/operators/mergeScan.ts
index 6e1e37c9ce..c9c520b296 100644
--- a/src/internal/operators/mergeScan.ts
+++ b/src/internal/operators/mergeScan.ts
@@ -61,11 +61,10 @@ import { mergeInternals } from './mergeInternals';
  * @see {@link scan}
  * @see {@link switchScan}
  *
- * @param {function(acc: R, value: T): Observable<R>} accumulator
- * The accumulator function called on each source value.
+ * @param accumulator The accumulator function called on each source value.
  * @param seed The initial accumulation value.
- * @param {number} [concurrent=Infinity] Maximum number of
- * input Observables being subscribed to concurrently.
+ * @param concurrent Maximum number of input Observables being subscribed to
+ * concurrently.
  * @return A function that returns an Observable of the accumulated values.
  */
 export function mergeScan<T, R>(
diff --git a/src/internal/operators/min.ts b/src/internal/operators/min.ts
index bef78d1c50..41dcd09c21 100644
--- a/src/internal/operators/min.ts
+++ b/src/internal/operators/min.ts
@@ -3,8 +3,9 @@ import { MonoTypeOperatorFunction } from '../types';
 import { isFunction } from '../util/isFunction';
 
 /**
- * The Min operator operates on an Observable that emits numbers (or items that can be compared with a provided function),
- * and when source Observable completes it emits a single item: the item with the smallest value.
+ * The `min` operator operates on an Observable that emits numbers (or items that
+ * can be compared with a provided function), and when source Observable completes
+ * it emits a single item: the item with the smallest value.
  *
  * ![](min.png)
  *
@@ -43,8 +44,8 @@ import { isFunction } from '../util/isFunction';
  *
  * @see {@link max}
  *
- * @param {Function} [comparer] - Optional comparer function that it will use instead of its default to compare the
- * value of two items.
+ * @param comparer Optional comparer function that it will use instead of its
+ * default to compare the value of two items.
  * @return A function that returns an Observable that emits item with the
  * smallest value.
  */
diff --git a/src/internal/operators/onErrorResumeNextWith.ts b/src/internal/operators/onErrorResumeNextWith.ts
index 9bcac812a4..9355c3fa54 100644
--- a/src/internal/operators/onErrorResumeNextWith.ts
+++ b/src/internal/operators/onErrorResumeNextWith.ts
@@ -76,7 +76,7 @@ export function onErrorResumeNextWith<T, A extends readonly unknown[]>(
  * @see {@link concat}
  * @see {@link catchError}
  *
- * @param {...ObservableInput} sources Observables passed either directly or as an array.
+ * @param sources `ObservableInput`s passed either directly or as an array.
  * @return A function that returns an Observable that emits values from source
  * Observable, but - if it errors - subscribes to the next passed Observable
  * and so on, until it completes or runs out of Observables.
diff --git a/src/internal/operators/partition.ts b/src/internal/operators/partition.ts
index 9b02a0c0b9..9f29f8540f 100644
--- a/src/internal/operators/partition.ts
+++ b/src/internal/operators/partition.ts
@@ -41,18 +41,17 @@ import { UnaryFunction } from '../types';
  *
  * @see {@link filter}
  *
- * @param {function(value: T, index: number): boolean} predicate A function that
- * evaluates each value emitted by the source Observable. If it returns `true`,
- * the value is emitted on the first Observable in the returned array, if
- * `false` the value is emitted on the second Observable in the array. The
- * `index` parameter is the number `i` for the i-th source emission that has
- * happened since the subscription, starting from the number `0`.
- * @param {any} [thisArg] An optional argument to determine the value of `this`
- * in the `predicate` function.
+ * @param predicate A function that evaluates each value emitted by the source
+ * Observable. If it returns `true`, the value is emitted on the first Observable
+ * in the returned array, if `false` the value is emitted on the second Observable
+ * in the array. The `index` parameter is the number `i` for the i-th source
+ * emission that has happened since the subscription, starting from the number `0`.
+ * @param thisArg An optional argument to determine the value of `this` in the
+ * `predicate` function.
  * @return A function that returns an array with two Observables: one with
  * values that passed the predicate, and another with values that did not pass
  * the predicate.
- * @deprecated Replaced with the `partition` static creation function. Will be removed in v8.
+ * @deprecated Replaced with the {@link partition} static creation function. Will be removed in v8.
  */
 export function partition<T>(
   predicate: (value: T, index: number) => boolean,
diff --git a/src/internal/operators/publish.ts b/src/internal/operators/publish.ts
index 105cd36729..6a4270564b 100644
--- a/src/internal/operators/publish.ts
+++ b/src/internal/operators/publish.ts
@@ -78,7 +78,7 @@ export function publish<T, O extends ObservableInput<any>>(selector: (shared: Ob
  * @see {@link publishReplay}
  * @see {@link publishBehavior}
  *
- * @param {Function} [selector] - Optional selector function which can use the multicasted source sequence as many times
+ * @param selector Optional selector function which can use the multicasted source sequence as many times
  * as needed, without causing multiple subscriptions to the source sequence.
  * Subscribers to the given source will receive all notifications of the source from the time of the subscription on.
  * @return A function that returns a ConnectableObservable that upon connection
diff --git a/src/internal/operators/reduce.ts b/src/internal/operators/reduce.ts
index c9bdda0543..5ee565e9d0 100644
--- a/src/internal/operators/reduce.ts
+++ b/src/internal/operators/reduce.ts
@@ -51,9 +51,8 @@ export function reduce<V, A, S = A>(accumulator: (acc: A | S, value: V, index: n
  * @see {@link mergeScan}
  * @see {@link scan}
  *
- * @param {function(acc: A, value: V, index: number): A} accumulator The accumulator function
- * called on each source value.
- * @param {A} [seed] The initial accumulation value.
+ * @param accumulator The accumulator function called on each source value.
+ * @param seed The initial accumulation value.
  * @return A function that returns an Observable that emits a single value that
  * is the result of accumulating the values emitted by the source Observable.
  */
diff --git a/src/internal/operators/repeat.ts b/src/internal/operators/repeat.ts
index fa0b3a3ab2..21a8cce09c 100644
--- a/src/internal/operators/repeat.ts
+++ b/src/internal/operators/repeat.ts
@@ -110,8 +110,8 @@ export interface RepeatConfig {
  * @see {@link repeatWhen}
  * @see {@link retry}
  *
- * @param count The number of times the source Observable items are repeated, a count of 0 will yield
- * an empty Observable.
+ * @param countOrConfig Either the number of times the source Observable items are repeated
+ * (a count of 0 will yield an empty Observable) or a {@link RepeatConfig} object.
  */
 export function repeat<T>(countOrConfig?: number | RepeatConfig): MonoTypeOperatorFunction<T> {
   let count = Infinity;
diff --git a/src/internal/operators/repeatWhen.ts b/src/internal/operators/repeatWhen.ts
index 5e55ca07f4..403b2c6c4e 100644
--- a/src/internal/operators/repeatWhen.ts
+++ b/src/internal/operators/repeatWhen.ts
@@ -36,7 +36,7 @@ import { createOperatorSubscriber } from './OperatorSubscriber';
  *
  * @param notifier Function that receives an Observable of notifications with
  * which a user can `complete` or `error`, aborting the repetition.
- * @return A function that returns an `ObservableInput` that mirrors the source
+ * @return A function that returns an Observable that mirrors the source
  * Observable with the exception of a `complete`.
  * @deprecated Will be removed in v9 or v10. Use {@link repeat}'s {@link RepeatConfig#delay delay} option instead.
  * Instead of `repeatWhen(() => notify$)`, use: `repeat({ delay: () => notify$ })`.
diff --git a/src/internal/operators/retry.ts b/src/internal/operators/retry.ts
index fe03385a59..dbb5164315 100644
--- a/src/internal/operators/retry.ts
+++ b/src/internal/operators/retry.ts
@@ -76,7 +76,8 @@ export function retry<T>(config: RetryConfig): MonoTypeOperatorFunction<T>;
  *
  * @see {@link retryWhen}
  *
- * @param configOrCount - Either number of retry attempts before failing or a {@link RetryConfig} object.
+ * @param configOrCount Either number of retry attempts before failing or a
+ * {@link RetryConfig} object.
  * @return A function that returns an Observable that will resubscribe to the
  * source stream when the source stream errors, at most `count` times.
  */
diff --git a/src/internal/operators/retryWhen.ts b/src/internal/operators/retryWhen.ts
index 8090e5f619..0b83ad6539 100644
--- a/src/internal/operators/retryWhen.ts
+++ b/src/internal/operators/retryWhen.ts
@@ -58,7 +58,7 @@ import { createOperatorSubscriber } from './OperatorSubscriber';
  *
  * @param notifier Function that receives an Observable of notifications with which a
  * user can `complete` or `error`, aborting the retry.
- * @return A function that returns an `ObservableInput` that mirrors the source
+ * @return A function that returns an Observable that mirrors the source
  * Observable with the exception of an `error`.
  * @deprecated Will be removed in v9 or v10, use {@link retry}'s `delay` option instead.
  * Will be removed in v9 or v10. Use {@link retry}'s {@link RetryConfig#delay delay} option instead.
diff --git a/src/internal/operators/sampleTime.ts b/src/internal/operators/sampleTime.ts
index 6558fa03ab..e4af047801 100644
--- a/src/internal/operators/sampleTime.ts
+++ b/src/internal/operators/sampleTime.ts
@@ -38,10 +38,10 @@ import { interval } from '../observable/interval';
  * @see {@link sample}
  * @see {@link throttleTime}
  *
- * @param {number} period The sampling period expressed in milliseconds or the
- * time unit determined internally by the optional `scheduler`.
- * @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for
- * managing the timers that handle the sampling.
+ * @param period The sampling period expressed in milliseconds or the time unit
+ * determined internally by the optional `scheduler`.
+ * @param scheduler The {@link SchedulerLike} to use for managing the timers
+ * that handle the sampling.
  * @return A function that returns an Observable that emits the results of
  * sampling the values emitted by the source Observable at the specified time
  * interval.
diff --git a/src/internal/operators/single.ts b/src/internal/operators/single.ts
index b91ab2acce..59c21c571e 100644
--- a/src/internal/operators/single.ts
+++ b/src/internal/operators/single.ts
@@ -16,15 +16,15 @@ export function single<T>(predicate?: (value: T, index: number, source: Observab
  * predicate is provided, then it will assert that the observable
  * only emits one value.
  *
- * In the event that the observable is empty, it will throw an
- * {@link EmptyError}.
+ * If the source Observable did not emit `next` before completion, it
+ * will emit an {@link EmptyError} to the Observer's `error` callback.
  *
  * In the event that two values are found that match the predicate,
  * or when there are two values emitted and no predicate, it will
- * throw a {@link SequenceError}
+ * emit a {@link SequenceError} to the Observer's `error` callback.
  *
  * In the event that no values match the predicate, if one is provided,
- * it will throw a {@link NotFoundError}
+ * it will emit a {@link NotFoundError} to the Observer's `error` callback.
  *
  * ## Example
  *
@@ -77,12 +77,16 @@ export function single<T>(predicate?: (value: T, index: number, source: Observab
  * @see {@link findIndex}
  * @see {@link elementAt}
  *
- * @throws {NotFoundError} Delivers an NotFoundError to the Observer's `error`
+ * @throws {NotFoundError} Delivers a `NotFoundError` to the Observer's `error`
  * callback if the Observable completes before any `next` notification was sent.
- * @throws {SequenceError} Delivers a SequenceError if more than one value is emitted that matches the
- * provided predicate. If no predicate is provided, will deliver a SequenceError if more
- * than one value comes from the source
- * @param {Function} predicate - A predicate function to evaluate items emitted by the source Observable.
+ * @throws {SequenceError} Delivers a `SequenceError` if more than one value is
+ * emitted that matches the provided predicate. If no predicate is provided, it
+ * will deliver a `SequenceError` if more than one value comes from the source.
+ * @throws {EmptyError} Delivers an `EmptyError` if no values were `next`ed prior
+ * to completion.
+ *
+ * @param predicate A predicate function to evaluate items emitted by the source
+ * Observable.
  * @return A function that returns an Observable that emits the single item
  * emitted by the source Observable that matches the predicate.
  */
diff --git a/src/internal/operators/skip.ts b/src/internal/operators/skip.ts
index 76e3eff2df..424ad65178 100644
--- a/src/internal/operators/skip.ts
+++ b/src/internal/operators/skip.ts
@@ -30,7 +30,7 @@ import { filter } from './filter';
  * @see {@link skipUntil}
  * @see {@link skipLast}
  *
- * @param {Number} count - The number of times, items emitted by source Observable should be skipped.
+ * @param count The number of times, items emitted by source Observable should be skipped.
  * @return A function that returns an Observable that skips the first `count`
  * values emitted by the source Observable.
  */
diff --git a/src/internal/operators/skipWhile.ts b/src/internal/operators/skipWhile.ts
index 68aeca655c..84b7379846 100644
--- a/src/internal/operators/skipWhile.ts
+++ b/src/internal/operators/skipWhile.ts
@@ -45,7 +45,7 @@ export function skipWhile<T>(predicate: (value: T, index: number) => boolean): M
  * @see {@link skipUntil}
  * @see {@link skipLast}
  *
- * @param {Function} predicate - A function to test each item emitted from the source Observable.
+ * @param predicate A function to test each item emitted from the source Observable.
  * @return A function that returns an Observable that begins emitting items
  * emitted by the source Observable when the specified predicate becomes false.
  */
diff --git a/src/internal/operators/switchMap.ts b/src/internal/operators/switchMap.ts
index 4ba293e6e7..0ded7ba9fd 100644
--- a/src/internal/operators/switchMap.ts
+++ b/src/internal/operators/switchMap.ts
@@ -75,9 +75,8 @@ export function switchMap<T, R, O extends ObservableInput<any>>(
  * @see {@link switchAll}
  * @see {@link switchMapTo}
  *
- * @param {function(value: T, index: number): ObservableInput} project A function
- * that, when applied to an item emitted by the source Observable, returns an
- * Observable.
+ * @param project A function that, when applied to an item emitted by the source
+ * Observable, returns an Observable.
  * @return A function that returns an Observable that emits the result of
  * applying the projection function (and the optional deprecated
  * `resultSelector`) to each item emitted by the source Observable and taking
diff --git a/src/internal/operators/switchMapTo.ts b/src/internal/operators/switchMapTo.ts
index 28a45c1ccc..9819bdf1cc 100644
--- a/src/internal/operators/switchMapTo.ts
+++ b/src/internal/operators/switchMapTo.ts
@@ -47,8 +47,8 @@ export function switchMapTo<T, R, O extends ObservableInput<unknown>>(
  * @see {@link switchMap}
  * @see {@link mergeMapTo}
  *
- * @param {ObservableInput} innerObservable An Observable to replace each value from
- * the source Observable.
+ * @param innerObservable An `ObservableInput` to replace each value from the
+ * source Observable.
  * @return A function that returns an Observable that emits items from the
  * given `innerObservable` (and optionally transformed through the deprecated
  * `resultSelector`) every time a value is emitted on the source Observable,
diff --git a/src/internal/operators/takeUntil.ts b/src/internal/operators/takeUntil.ts
index 8ac6c23289..177141d356 100644
--- a/src/internal/operators/takeUntil.ts
+++ b/src/internal/operators/takeUntil.ts
@@ -37,9 +37,8 @@ import { noop } from '../util/noop';
  * @see {@link takeWhile}
  * @see {@link skip}
  *
- * @param {Observable} notifier The Observable whose first emitted value will
- * cause the output Observable of `takeUntil` to stop emitting values from the
- * source Observable.
+ * @param notifier The `ObservableInput` whose first emitted value will cause the output
+ * Observable of `takeUntil` to stop emitting values from the source Observable.
  * @return A function that returns an Observable that emits the values from the
  * source Observable until `notifier` emits its first value.
  */
diff --git a/src/internal/operators/takeWhile.ts b/src/internal/operators/takeWhile.ts
index 27da59d9ef..b48e34c06e 100644
--- a/src/internal/operators/takeWhile.ts
+++ b/src/internal/operators/takeWhile.ts
@@ -43,11 +43,11 @@ export function takeWhile<T>(predicate: (value: T, index: number) => boolean, in
  * @see {@link takeUntil}
  * @see {@link skip}
  *
- * @param {function(value: T, index: number): boolean} predicate A function that
- * evaluates a value emitted by the source Observable and returns a boolean.
- * Also takes the (zero-based) index as the second argument.
- * @param {boolean} inclusive When set to `true` the value that caused
- * `predicate` to return `false` will also be emitted.
+ * @param predicate A function that evaluates a value emitted by the source
+ * Observable and returns a boolean. Also takes the (zero-based) index as the
+ * second argument.
+ * @param inclusive When set to `true` the value that caused `predicate` to
+ * return `false` will also be emitted.
  * @return A function that returns an Observable that emits values from the
  * source Observable so long as each value satisfies the condition defined by
  * the `predicate`, then completes.
diff --git a/src/internal/operators/timeInterval.ts b/src/internal/operators/timeInterval.ts
index 5baa1457d0..6a58ab2209 100644
--- a/src/internal/operators/timeInterval.ts
+++ b/src/internal/operators/timeInterval.ts
@@ -38,7 +38,7 @@ import { createOperatorSubscriber } from './OperatorSubscriber';
  * // { value: 2, interval: 1000 }
  * ```
  *
- * @param {SchedulerLike} [scheduler] Scheduler used to get the current time.
+ * @param scheduler Scheduler used to get the current time.
  * @return A function that returns an Observable that emits information about
  * value and interval.
  */
diff --git a/src/internal/operators/timeout.ts b/src/internal/operators/timeout.ts
index 2035cae71c..a2e1635e6f 100644
--- a/src/internal/operators/timeout.ts
+++ b/src/internal/operators/timeout.ts
@@ -82,8 +82,6 @@ export interface TimeoutErrorCtor {
  * create your own error class and use that.
  *
  * @see {@link timeout}
- *
- * @class TimeoutError
  */
 export const TimeoutError: TimeoutErrorCtor = createErrorClass(
   (_super) =>
diff --git a/src/internal/operators/windowCount.ts b/src/internal/operators/windowCount.ts
index e568d42427..cf24e1bb1b 100644
--- a/src/internal/operators/windowCount.ts
+++ b/src/internal/operators/windowCount.ts
@@ -57,12 +57,11 @@ import { createOperatorSubscriber } from './OperatorSubscriber';
  * @see {@link windowWhen}
  * @see {@link bufferCount}
  *
- * @param {number} windowSize The maximum number of values emitted by each
- * window.
- * @param {number} [startWindowEvery] Interval at which to start a new window.
- * For example if `startWindowEvery` is `2`, then a new window will be started
- * on every other value from the source. A new window is started at the
- * beginning of the source by default.
+ * @param windowSize The maximum number of values emitted by each window.
+ * @param startWindowEvery Interval at which to start a new window. For example
+ * if `startWindowEvery` is `2`, then a new window will be started on every
+ * other value from the source. A new window is started at the beginning of the
+ * source by default.
  * @return A function that returns an Observable of windows, which in turn are
  * Observable of values.
  */
diff --git a/src/internal/operators/windowToggle.ts b/src/internal/operators/windowToggle.ts
index 95e596d4d4..a17bef5fa6 100644
--- a/src/internal/operators/windowToggle.ts
+++ b/src/internal/operators/windowToggle.ts
@@ -46,12 +46,10 @@ import { arrRemove } from '../util/arrRemove';
  * @see {@link windowWhen}
  * @see {@link bufferToggle}
  *
- * @param {Observable<O>} openings An observable of notifications to start new
- * windows.
- * @param {function(value: O): Observable} closingSelector A function that takes
- * the value emitted by the `openings` observable and returns an Observable,
- * which, when it emits a next notification, signals that the
- * associated window should complete.
+ * @param openings An observable of notifications to start new windows.
+ * @param closingSelector A function that takes the value emitted by the
+ * `openings` observable and returns an Observable, which, when it emits a next
+ * notification, signals that the associated window should complete.
  * @return A function that returns an Observable of windows, which in turn are
  * Observables.
  */
diff --git a/src/internal/operators/windowWhen.ts b/src/internal/operators/windowWhen.ts
index 860143f444..ec31be01f0 100644
--- a/src/internal/operators/windowWhen.ts
+++ b/src/internal/operators/windowWhen.ts
@@ -44,9 +44,10 @@ import { innerFrom } from '../observable/innerFrom';
  * @see {@link windowToggle}
  * @see {@link bufferWhen}
  *
- * @param {function(): Observable} closingSelector A function that takes no
- * arguments and returns an Observable that signals (on either `next` or
- * `complete`) when to close the previous window and start a new one.
+ * @param closingSelector A function that takes no arguments and returns an
+ * {@link ObservableInput} (that gets converted to Observable) that signals
+ * (on either `next` or `complete`) when to close the previous window and
+ * start a new one.
  * @return A function that returns an Observable of windows, which in turn are
  * Observables.
  */
diff --git a/src/internal/operators/withLatestFrom.ts b/src/internal/operators/withLatestFrom.ts
index 80576e18f2..6cd7e4a856 100644
--- a/src/internal/operators/withLatestFrom.ts
+++ b/src/internal/operators/withLatestFrom.ts
@@ -44,13 +44,14 @@ export function withLatestFrom<T, O extends unknown[], R>(
  *
  * @see {@link combineLatest}
  *
- * @param {ObservableInput} other An input Observable to combine with the source
- * Observable. More than one input Observables may be given as argument.
- * @param {Function} [project] Projection function for combining values
- * together. Receives all values in order of the Observables passed, where the
- * first parameter is a value from the source Observable. (e.g.
- * `a.pipe(withLatestFrom(b, c), map(([a1, b1, c1]) => a1 + b1 + c1))`). If this is not
- * passed, arrays will be emitted on the output Observable.
+ * @param inputs An input Observable to combine with the source Observable. More
+ * than one input Observables may be given as argument. If the last parameter is
+ * a function, it will be used as a projection function for combining values
+ * together. When the function is called, it receives all values in order of the
+ * Observables passed, where the first parameter is a value from the source
+ * Observable. (e.g.
+ * `a.pipe(withLatestFrom(b, c), map(([a1, b1, c1]) => a1 + b1 + c1))`). If this
+ * is not passed, arrays will be emitted on the output Observable.
  * @return A function that returns an Observable of projected values from the
  * most recent values from each input Observable, or an array of the most
  * recent values from each input Observable.
diff --git a/src/internal/scheduler/Action.ts b/src/internal/scheduler/Action.ts
index 6cf91bcb87..a9c543b8a5 100644
--- a/src/internal/scheduler/Action.ts
+++ b/src/internal/scheduler/Action.ts
@@ -13,8 +13,6 @@ import { SchedulerAction } from '../types';
  *   schedule(state?: T, delay: number = 0): Subscription;
  * }
  * ```
- *
- * @class Action<T>
  */
 export class Action<T> extends Subscription {
   constructor(scheduler: Scheduler, work: (this: SchedulerAction<T>, state?: T) => void) {
@@ -24,11 +22,11 @@ export class Action<T> extends Subscription {
    * Schedules this action on its parent {@link SchedulerLike} for execution. May be passed
    * some context object, `state`. May happen at some point in the future,
    * according to the `delay` parameter, if specified.
-   * @param {T} [state] Some contextual data that the `work` function uses when
-   * called by the Scheduler.
-   * @param {number} [delay] Time to wait before executing the work, where the
-   * time unit is implicit and defined by the Scheduler.
-   * @return {void}
+   * @param state Some contextual data that the `work` function uses when called by the
+   * Scheduler.
+   * @param delay Time to wait before executing the work, where the time unit is implicit
+   * and defined by the Scheduler.
+   * @return A subscription in order to be able to unsubscribe the scheduled work.
    */
   public schedule(state?: T, delay: number = 0): Subscription {
     return this;
diff --git a/src/internal/scheduler/AnimationFrameAction.ts b/src/internal/scheduler/AnimationFrameAction.ts
index f9c8f8e39d..502bbc7f16 100644
--- a/src/internal/scheduler/AnimationFrameAction.ts
+++ b/src/internal/scheduler/AnimationFrameAction.ts
@@ -33,7 +33,7 @@ export class AnimationFrameAction<T> extends AsyncAction<T> {
     // cancel the requested animation frame and set the scheduled flag to
     // undefined so the next AnimationFrameAction will request its own.
     const { actions } = scheduler;
-    if (id != null && actions[actions.length - 1]?.id !== id) {
+    if (id != null && id === scheduler._scheduled && actions[actions.length - 1]?.id !== id) {
       animationFrameProvider.cancelAnimationFrame(id as number);
       scheduler._scheduled = undefined;
     }
diff --git a/src/internal/scheduler/AnimationFrameScheduler.ts b/src/internal/scheduler/AnimationFrameScheduler.ts
index 640afa2488..1f21ffa164 100644
--- a/src/internal/scheduler/AnimationFrameScheduler.ts
+++ b/src/internal/scheduler/AnimationFrameScheduler.ts
@@ -13,8 +13,13 @@ export class AnimationFrameScheduler extends AsyncScheduler {
     // are removed from the actions array and that can shift actions that are
     // scheduled to be executed in a subsequent flush into positions at which
     // they are executed within the current flush.
-    const flushId = this._scheduled;
-    this._scheduled = undefined;
+    let flushId;
+    if (action) {
+      flushId = action.id;
+    } else {
+      flushId = this._scheduled;
+      this._scheduled = undefined;
+    }
 
     const { actions } = this;
     let error: any;
diff --git a/src/internal/scheduler/AsyncAction.ts b/src/internal/scheduler/AsyncAction.ts
index d7ffe51185..704b571047 100644
--- a/src/internal/scheduler/AsyncAction.ts
+++ b/src/internal/scheduler/AsyncAction.ts
@@ -84,7 +84,6 @@ export class AsyncAction<T> extends Action<T> {
 
   /**
    * Immediately executes this action and the `work` it contains.
-   * @return {any}
    */
   public execute(state: T, delay: number): any {
     if (this.closed) {
diff --git a/src/internal/scheduler/AsyncScheduler.ts b/src/internal/scheduler/AsyncScheduler.ts
index fc04d66236..b05e2e376a 100644
--- a/src/internal/scheduler/AsyncScheduler.ts
+++ b/src/internal/scheduler/AsyncScheduler.ts
@@ -8,7 +8,6 @@ export class AsyncScheduler extends Scheduler {
   /**
    * A flag to indicate whether the Scheduler is currently executing a batch of
    * queued actions.
-   * @type {boolean}
    * @internal
    */
   public _active: boolean = false;
@@ -16,7 +15,6 @@ export class AsyncScheduler extends Scheduler {
    * An internal ID used to track the latest asynchronous task such as those
    * coming from `setTimeout`, `setInterval`, `requestAnimationFrame`, and
    * others.
-   * @type {any}
    * @internal
    */
   public _scheduled: TimerHandle | undefined;
diff --git a/src/internal/scheduler/VirtualTimeScheduler.ts b/src/internal/scheduler/VirtualTimeScheduler.ts
index 310ac919bb..70fec02167 100644
--- a/src/internal/scheduler/VirtualTimeScheduler.ts
+++ b/src/internal/scheduler/VirtualTimeScheduler.ts
@@ -36,7 +36,6 @@ export class VirtualTimeScheduler extends AsyncScheduler {
   /**
    * Prompt the Scheduler to execute all of its queued actions, therefore
    * clearing its queue.
-   * @return {void}
    */
   public flush(): void {
     const { actions, maxFrames } = this;
diff --git a/src/internal/testing/TestScheduler.ts b/src/internal/testing/TestScheduler.ts
index 2ccdbc556d..0045166740 100644
--- a/src/internal/testing/TestScheduler.ts
+++ b/src/internal/testing/TestScheduler.ts
@@ -41,7 +41,6 @@ export class TestScheduler extends VirtualTimeScheduler {
    * The number of virtual time units each character in a marble diagram represents. If
    * the test scheduler is being used in "run mode", via the `run` method, this is temporarily
    * set to `1` for the duration of the `run` block, then set back to whatever value it was.
-   * @nocollapse
    */
   static frameTimeFactor = 10;
 
@@ -221,7 +220,6 @@ export class TestScheduler extends VirtualTimeScheduler {
     });
   }
 
-  /** @nocollapse */
   static parseMarblesAsSubscriptions(marbles: string | null, runMode = false): SubscriptionLog {
     if (typeof marbles !== 'string') {
       return new SubscriptionLog(Infinity);
@@ -319,7 +317,6 @@ export class TestScheduler extends VirtualTimeScheduler {
     }
   }
 
-  /** @nocollapse */
   static parseMarbles(
     marbles: string,
     values?: any,
diff --git a/src/internal/types.ts b/src/internal/types.ts
index a28e96a28c..b72eab3a11 100644
--- a/src/internal/types.ts
+++ b/src/internal/types.ts
@@ -31,6 +31,12 @@ export interface OperatorFunction<T, R> extends UnaryFunction<Observable<T>, Obs
 
 export type FactoryOrValue<T> = T | (() => T);
 
+/**
+ * A function type interface that describes a function that accepts and returns a parameter of the same type.
+ *
+ * Used to describe {@link OperatorFunction} with the only one type: `OperatorFunction<T, T>`.
+ *
+ */
 export interface MonoTypeOperatorFunction<T> extends OperatorFunction<T, T> {}
 
 /**
diff --git a/src/internal/util/ArgumentOutOfRangeError.ts b/src/internal/util/ArgumentOutOfRangeError.ts
index bd528ba7b7..9a89d7694b 100644
--- a/src/internal/util/ArgumentOutOfRangeError.ts
+++ b/src/internal/util/ArgumentOutOfRangeError.ts
@@ -17,8 +17,6 @@ export interface ArgumentOutOfRangeErrorCtor {
  * @see {@link elementAt}
  * @see {@link take}
  * @see {@link takeLast}
- *
- * @class ArgumentOutOfRangeError
  */
 export const ArgumentOutOfRangeError: ArgumentOutOfRangeErrorCtor = createErrorClass(
   (_super) =>
diff --git a/src/internal/util/EmptyError.ts b/src/internal/util/EmptyError.ts
index e2cbb9c0da..eb2c5e3159 100644
--- a/src/internal/util/EmptyError.ts
+++ b/src/internal/util/EmptyError.ts
@@ -19,11 +19,12 @@ export interface EmptyErrorCtor {
  * @see {@link single}
  * @see {@link firstValueFrom}
  * @see {@link lastValueFrom}
- *
- * @class EmptyError
  */
-export const EmptyError: EmptyErrorCtor = createErrorClass((_super) => function EmptyErrorImpl(this: any) {
-  _super(this);
-  this.name = 'EmptyError';
-  this.message = 'no elements in sequence';
-});
+export const EmptyError: EmptyErrorCtor = createErrorClass(
+  (_super) =>
+    function EmptyErrorImpl(this: any) {
+      _super(this);
+      this.name = 'EmptyError';
+      this.message = 'no elements in sequence';
+    }
+);
diff --git a/src/internal/util/NotFoundError.ts b/src/internal/util/NotFoundError.ts
index 8880b53473..ecd213fd3a 100644
--- a/src/internal/util/NotFoundError.ts
+++ b/src/internal/util/NotFoundError.ts
@@ -15,8 +15,6 @@ export interface NotFoundErrorCtor {
  * observable sequence.
  *
  * @see {@link operators/single}
- *
- * @class NotFoundError
  */
 export const NotFoundError: NotFoundErrorCtor = createErrorClass(
   (_super) =>
diff --git a/src/internal/util/SequenceError.ts b/src/internal/util/SequenceError.ts
index e959557df9..06483d0701 100644
--- a/src/internal/util/SequenceError.ts
+++ b/src/internal/util/SequenceError.ts
@@ -15,8 +15,6 @@ export interface SequenceErrorCtor {
  * values arriving on the observable.
  *
  * @see {@link operators/single}
- *
- * @class SequenceError
  */
 export const SequenceError: SequenceErrorCtor = createErrorClass(
   (_super) =>