12 files declare their use of AttachedAssetsInterface

AssetControllerBase.php in core/modules/system/src/Controller/AssetControllerBase.php
AssetResolverTest.php in core/tests/Drupal/Tests/Core/Asset/AssetResolverTest.php
BigPipe.php in core/modules/big_pipe/src/Render/BigPipe.php
ckeditor5.module in core/modules/ckeditor5/ckeditor5.module
common_test.module in core/modules/system/tests/modules/common_test/common_test.module
Helper module for the Common tests.
CssAssetController.php in core/modules/system/src/Controller/CssAssetController.php
HtmlResponseAttachmentsProcessor.php in core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php
JsAssetController.php in core/modules/system/src/Controller/JsAssetController.php
locale.module in core/modules/locale/locale.module
Enables the translation of the user interface to languages other than English.
settings_tray.module in core/modules/settings_tray/settings_tray.module
Allows configuring blocks and other configuration from the site front-end.
system.module in core/modules/system/system.module
Configuration system that lets administrators modify the workings of the site.
user.module in core/modules/user/user.module
Enables the user registration and login system.

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