20 files declare their use of EntityChangedInterface in Drupal 8

BlockContentInterface.php in core/modules/block_content/src/BlockContentInterface.php

CommentInterface.php in core/modules/comment/src/CommentInterface.php

CommentStatistics.php in core/modules/comment/src/CommentStatistics.php

ContentTranslationHandler.php in core/modules/content_translation/src/ContentTranslationHandler.php

ContentTranslationUITestBase.php in core/modules/content_translation/src/Tests/ContentTranslationUITestBase.php

ContentTranslationUITestBase.php in core/modules/content_translation/tests/src/Functional/ContentTranslationUITestBase.php

EntityChangedActionDeriver.php in core/lib/Drupal/Core/Action/Plugin/Action/Derivative/EntityChangedActionDeriver.php

EntityContentComplete.php in core/modules/migrate/src/Plugin/migrate/destination/EntityContentComplete.php

EntityTestConstraints.php in core/modules/system/tests/modules/entity_test/src/Entity/EntityTestConstraints.php

EntityTestMulChanged.php in core/modules/system/tests/modules/entity_test/src/Entity/EntityTestMulChanged.php

FileInterface.php in core/modules/file/src/FileInterface.php

MediaInterface.php in core/modules/media/src/MediaInterface.php

MenuLinkContentInterface.php in core/modules/menu_link_content/src/MenuLinkContentInterface.php

NestedEntityTestForm.php in core/modules/field/tests/modules/field_test/src/Form/NestedEntityTestForm.php

NodeInterface.php in core/modules/node/src/NodeInterface.php

QuickEditFieldForm.php in core/modules/quickedit/src/Form/QuickEditFieldForm.php

ShortcutTranslationUITest.php in core/modules/shortcut/tests/src/Functional/ShortcutTranslationUITest.php

TermInterface.php in core/modules/taxonomy/src/TermInterface.php

UserInterface.php in core/modules/user/src/UserInterface.php

WorkspaceInterface.php in core/modules/workspaces/src/WorkspaceInterface.php