12 files declare their use of ConfigEntityTypeInterface

ConfigEntityNormalizerTest.php in core/modules/serialization/tests/src/Unit/Normalizer/ConfigEntityNormalizerTest.php
ConfigManager.php in core/lib/Drupal/Core/Config/ConfigManager.php
DefaultHtmlRouteProvider.php in core/lib/Drupal/Core/Entity/Routing/DefaultHtmlRouteProvider.php
DefaultHtmlRouteProviderTest.php in core/tests/Drupal/Tests/Core/Entity/Routing/DefaultHtmlRouteProviderTest.php
EntityFormDisplayAccessControlHandlerTest.php in core/tests/Drupal/Tests/Core/Entity/Access/EntityFormDisplayAccessControlHandlerTest.php
EntityMethodDeriver.php in core/lib/Drupal/Core/Config/Action/Plugin/ConfigAction/Deriver/EntityMethodDeriver.php
EntityRepository.php in core/lib/Drupal/Core/Entity/EntityRepository.php
FieldStorageConfigAccessControlHandlerTest.php in core/modules/field/tests/src/Unit/FieldStorageConfigAccessControlHandlerTest.php
QueryFactory.php in core/lib/Drupal/Core/Config/Entity/Query/QueryFactory.php
RequiredConfigDependenciesConstraintValidator.php in core/lib/Drupal/Core/Config/Plugin/Validation/Constraint/RequiredConfigDependenciesConstraintValidator.php
ResourceTypeRepository.php in core/modules/jsonapi/src/ResourceType/ResourceTypeRepository.php
TemporaryQueryGuard.php in core/modules/jsonapi/src/Access/TemporaryQueryGuard.php

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