Files located in data directory are used only for testing purposes.

Here the list of files in the data directory

.nvmrc, .tools-versions and package.json are used to test node-version-file logic
package-lock.json, pnpm-lock.yaml and yarn.lock are used to test cache logic
versions-manifest.json is used for unit testing to check downloading Node.js versions from the node-versions repository.
node-dist-index.json is used for unit testing to check downloading Node.js versions from the official site. The file was constructed from https://nodejs.org/dist/index.json
node-rc-index.json is used for unit testing to check downloading Node.js rc versions from the official site. The file was constructed from https://nodejs.org/download/rc/index.json
node-nightly-index.json is used for unit testing to check downloading Node.js nightly builds from the official site. The file was constructed from https://nodejs.org/download/nightly/index.json