diff --git a/frontend/asset_mapper.rst b/frontend/asset_mapper.rst
index 57a88f77f23..648b158ebb1 100644
--- a/frontend/asset_mapper.rst
+++ b/frontend/asset_mapper.rst
@@ -289,17 +289,27 @@ Preloading and Initializing "app.js"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In addition to the importmap, the ``{{ importmap() }}`` Twig function also renders
-an `ES module shim`_ and a few other things, like a set of "preloads":
+an `ES module shim`_ by default. You can configure this in your ``config/packages/asset_mapper.yaml``
+configuration file:
-.. code-block:: html
+.. code-block:: yaml
-
-
+ framework:
+ asset_mapper:
+ importmap_polyfill: false # disable the shim ...
+ # importmap_polyfill: 'https://...' # ... or pass some custom URL
In ``importmap.php``, each entry can have a ``preload`` option. If set to ``true``,
a ```` tag is rendered for that entry as well as for
any JavaScript files it imports (this happens for "relative" - ``./`` or ``../`` -
-imports only). This is a performance optimization and you can learn more about below
+imports only):
+
+.. code-block:: html
+
+
+
+
+This is a performance optimization and you can learn more about below
in :ref:`Performance: Add Preloading `.
.. _importmap-app-entry: