13 files declare their use of CKEditor5PluginDefault

Alignment.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/Alignment.php
DrupalAspectsOfCKEditor5Plugin.php in core/modules/ckeditor5/src/Annotation/DrupalAspectsOfCKEditor5Plugin.php
GlobalAttribute.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/GlobalAttribute.php
Heading.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/Heading.php
Image.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/Image.php
ImageResize.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/ImageResize.php
Language.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/Language.php
ListPlugin.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/ListPlugin.php
Media.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/Media.php
MediaLibrary.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/MediaLibrary.php
SneakySuperset.php in core/modules/ckeditor5/tests/modules/ckeditor5_plugin_elements_subset/src/Plugin/CKEditor5Plugin/SneakySuperset.php
SourceEditing.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/SourceEditing.php
Style.php in core/modules/ckeditor5/src/Plugin/CKEditor5Plugin/Style.php

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