19 files declare their use of EntityViewMode

CKEditorIntegrationTest.php in core/modules/media/tests/src/FunctionalJavascript/CKEditorIntegrationTest.php
comment.module in core/modules/comment/comment.module
Enables users to comment on published content.
CommentIntegrationTest.php in core/modules/comment/tests/src/Kernel/CommentIntegrationTest.php
CommentInterfaceTest.php in core/modules/comment/tests/src/Functional/CommentInterfaceTest.php
DisplayApiTest.php in core/modules/field/tests/src/Kernel/DisplayApiTest.php
DisplayModeUpdateTest.php in core/modules/field/tests/src/Kernel/DisplayModeUpdateTest.php
EntityDisplayModeTest.php in core/modules/field_ui/tests/src/Functional/EntityDisplayModeTest.php
EntityDisplayTest.php in core/modules/field_ui/tests/src/Kernel/EntityDisplayTest.php
EntityViewBuilderTest.php in core/tests/Drupal/KernelTests/Core/Entity/EntityViewBuilderTest.php
EntityViewModeResourceTestBase.php in core/tests/Drupal/FunctionalTests/Rest/EntityViewModeResourceTestBase.php
EntityViewModeTest.php in core/modules/jsonapi/tests/src/Functional/EntityViewModeTest.php
FieldRenderedEntityTest.php in core/modules/views/tests/src/Kernel/Handler/FieldRenderedEntityTest.php
FieldUIRouteTest.php in core/modules/field_ui/tests/src/Functional/FieldUIRouteTest.php
MediaEmbedFilterTestBase.php in core/modules/media/tests/src/Kernel/MediaEmbedFilterTestBase.php
media_library.post_update.php in core/modules/media_library/media_library.post_update.php
Post update functions for Media Library.
MigrateViewModesTest.php in core/modules/node/tests/src/Kernel/Migrate/d6/MigrateViewModesTest.php
MigrateViewModesTest.php in core/modules/field/tests/src/Kernel/Migrate/d7/MigrateViewModesTest.php
RollbackViewModesTest.php in core/modules/field/tests/src/Kernel/Migrate/d7/RollbackViewModesTest.php
RowUITest.php in core/modules/views_ui/tests/src/Functional/RowUITest.php

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