15 files declare their use of EntityOwnerInterface in Drupal 9

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

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

ContentModerationStateInterface.php in core/modules/content_moderation/src/Entity/ContentModerationStateInterface.php

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

DefaultSelection.php in core/lib/Drupal/Core/Entity/Plugin/EntityReferenceSelection/DefaultSelection.php

EntityReferenceAutocompleteWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EntityReferenceAutocompleteWidget.php

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

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

LatestRevisionCheck.php in core/modules/content_moderation/src/Access/LatestRevisionCheck.php

LatestRevisionCheckTest.php in core/modules/content_moderation/tests/src/Unit/LatestRevisionCheckTest.php

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

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

ResourceTestBase.php in core/modules/jsonapi/tests/src/Functional/ResourceTestBase.php

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

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