70 files declare their use of ConfigEntityInterface

Action.php in core/modules/system/src/Entity/Action.php
ActionConfigEntityInterface.php in core/modules/system/src/ActionConfigEntityInterface.php
AdminPathConfigEntityConverter.php in core/lib/Drupal/Core/ParamConverter/AdminPathConfigEntityConverter.php
AssertConfigEntityImportTrait.php in core/modules/config/tests/src/Traits/AssertConfigEntityImportTrait.php
Block.php in core/modules/block/src/Entity/Block.php
BlockContentTypeInterface.php in core/modules/block_content/src/BlockContentTypeInterface.php
BlockInterface.php in core/modules/block/src/BlockInterface.php
BlockValidationTest.php in core/modules/block/tests/src/Kernel/BlockValidationTest.php
CommentTypeInterface.php in core/modules/comment/src/CommentTypeInterface.php
ConfigEntityDenormalizer.php in core/modules/jsonapi/src/Normalizer/ConfigEntityDenormalizer.php
ConfigEntityMapper.php in core/modules/config_translation/src/ConfigEntityMapper.php
ConfigEntityMapperInterface.php in core/modules/config_translation/src/ConfigEntityMapperInterface.php
ConfigEntityNormalizer.php in core/modules/serialization/src/Normalizer/ConfigEntityNormalizer.php
ConfigEntityStorageTest.php in core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityStorageTest.php
ConfigEntityValidationTestBase.php in core/tests/Drupal/KernelTests/Core/Config/ConfigEntityValidationTestBase.php
ConfigFieldMapper.php in core/modules/config_translation/src/ConfigFieldMapper.php
ConfigManager.php in core/lib/Drupal/Core/Config/ConfigManager.php
ConfigSingleExportForm.php in core/modules/config/src/Form/ConfigSingleExportForm.php
ConfigSingleImportForm.php in core/modules/config/src/Form/ConfigSingleImportForm.php
ConfigTest.php in core/modules/config/tests/config_test/src/Entity/ConfigTest.php
ConfigTestInterface.php in core/modules/config/tests/config_test/src/ConfigTestInterface.php
ConfigurableLanguageInterface.php in core/modules/language/src/ConfigurableLanguageInterface.php
config_translation.module in core/modules/config_translation/config_translation.module
Configuration Translation module.
ContactFormInterface.php in core/modules/contact/src/ContactFormInterface.php
ContentLanguageSettingsInterface.php in core/modules/language/src/ContentLanguageSettingsInterface.php
DateFormat.php in core/lib/Drupal/Core/Datetime/Entity/DateFormat.php
DateFormatInterface.php in core/lib/Drupal/Core/Datetime/DateFormatInterface.php
EditorInterface.php in core/modules/editor/src/EditorInterface.php
EntityDeleteForm.php in core/lib/Drupal/Core/Entity/EntityDeleteForm.php
EntityDeriver.php in core/lib/Drupal/Core/Entity/Plugin/DataType/Deriver/EntityDeriver.php
EntityDisplayBase.php in core/lib/Drupal/Core/Entity/EntityDisplayBase.php
EntityDisplayInterface.php in core/lib/Drupal/Core/Entity/Display/EntityDisplayInterface.php
EntityDisplayModeBase.php in core/lib/Drupal/Core/Entity/EntityDisplayModeBase.php
EntityDisplayModeInterface.php in core/lib/Drupal/Core/Entity/EntityDisplayModeInterface.php
EntityMethod.php in core/lib/Drupal/Core/Config/Action/Plugin/ConfigAction/EntityMethod.php
EntityResource.php in core/modules/jsonapi/src/Controller/EntityResource.php
EntityResourceRestTestCoverageTest.php in core/modules/rest/tests/src/Kernel/EntityResource/EntityResourceRestTestCoverageTest.php
EntityResourceTestBase.php in core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
EntityTypedDataDefinitionTest.php in core/tests/Drupal/KernelTests/Core/Entity/EntityTypedDataDefinitionTest.php
EntityTypeTest.php in core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php
Exists.php in core/lib/Drupal/Core/Config/Action/Exists.php
FieldConfigDeleteForm.php in core/modules/field_ui/src/Form/FieldConfigDeleteForm.php
FieldConfigInterface.php in core/modules/field/src/FieldConfigInterface.php
FieldConfigInterface.php in core/lib/Drupal/Core/Field/FieldConfigInterface.php
FieldStorageConfigInterface.php in core/modules/field/src/FieldStorageConfigInterface.php
FilterFormatInterface.php in core/modules/filter/src/FilterFormatInterface.php
ImageStyleInterface.php in core/modules/image/src/ImageStyleInterface.php
ImmutablePropertiesConstraintValidator.php in core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/ImmutablePropertiesConstraintValidator.php
ImmutablePropertiesConstraintValidatorTest.php in core/tests/Drupal/KernelTests/Core/Entity/ImmutablePropertiesConstraintValidatorTest.php
KeyValueEntityStorageTest.php in core/tests/Drupal/Tests/Core/Entity/KeyValueStore/KeyValueEntityStorageTest.php
MediaTypeInterface.php in core/modules/media/src/MediaTypeInterface.php
MenuInterface.php in core/modules/system/src/MenuInterface.php
NodeTypeInterface.php in core/modules/node/src/NodeTypeInterface.php
NodeTypeMapper.php in core/modules/node/src/ConfigTranslation/NodeTypeMapper.php
RequiredConfigDependenciesConstraintValidator.php in core/lib/Drupal/Core/Config/Plugin/Validation/Constraint/RequiredConfigDependenciesConstraintValidator.php
ResourceObject.php in core/modules/jsonapi/src/JsonApiResource/ResourceObject.php
ResourceTestBase.php in core/modules/jsonapi/tests/src/Functional/ResourceTestBase.php
ResponsiveImageStyleInterface.php in core/modules/responsive_image/src/ResponsiveImageStyleInterface.php
RestResourceConfigInterface.php in core/modules/rest/src/RestResourceConfigInterface.php
RevisionableEntityBundleInterface.php in core/lib/Drupal/Core/Entity/RevisionableEntityBundleInterface.php
RoleInterface.php in core/modules/user/src/RoleInterface.php
SchemaCheckTrait.php in core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
SearchPage.php in core/modules/search/src/Entity/SearchPage.php
SearchPageInterface.php in core/modules/search/src/SearchPageInterface.php
ShortcutSetInterface.php in core/modules/shortcut/src/ShortcutSetInterface.php
TestCoverageTest.php in core/modules/jsonapi/tests/src/Kernel/TestCoverageTest.php
TourInterface.php in core/modules/tour/src/TourInterface.php
ViewEntityInterface.php in core/modules/views/src/ViewEntityInterface.php
VocabularyInterface.php in core/modules/taxonomy/src/VocabularyInterface.php
WorkflowInterface.php in core/modules/workflows/src/WorkflowInterface.php

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