18 files declare their use of ContextDefinition

ContextAwarePluginBaseTest.php in core/tests/Drupal/KernelTests/Core/Plugin/Context/ContextAwarePluginBaseTest.php
ContextAwarePluginTraitTest.php in core/tests/Drupal/KernelTests/Core/Plugin/Context/ContextAwarePluginTraitTest.php
ContextDefinitionIsSatisfiedTest.php in core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionIsSatisfiedTest.php
ContextDefinitionTest.php in core/tests/Drupal/KernelTests/Core/Plugin/ContextDefinitionTest.php
ContextDefinitionTest.php in core/tests/Drupal/KernelTests/Core/Plugin/Annotation/ContextDefinitionTest.php
ContextDefinitionTest.php in core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionTest.php
ContextHandlerTest.php in core/tests/Drupal/Tests/Core/Plugin/ContextHandlerTest.php
Contains \Drupal\Tests\Core\Plugin\ContextHandlerTest.
ContextTypedDataTest.php in core/tests/Drupal/KernelTests/Core/Plugin/ContextTypedDataTest.php
CurrentLanguageContext.php in core/lib/Drupal/Core/Language/ContextProvider/CurrentLanguageContext.php
EntityContextDefinitionIsSatisfiedTest.php in core/tests/Drupal/Tests/Core/Plugin/Context/EntityContextDefinitionIsSatisfiedTest.php
EntityConverter.php in core/lib/Drupal/Core/ParamConverter/EntityConverter.php
EntityConverterTest.php in core/tests/Drupal/Tests/Core/ParamConverter/EntityConverterTest.php
EntityRepositoryTest.php in core/tests/Drupal/KernelTests/Core/Entity/EntityRepositoryTest.php
InheritedContextDefinition.php in core/tests/Drupal/Tests/Core/Plugin/Fixtures/InheritedContextDefinition.php
LayoutBuilderIntegration.php in core/modules/quickedit/src/LayoutBuilderIntegration.php
LazyContextRepositoryTest.php in core/tests/Drupal/Tests/Core/Plugin/Context/LazyContextRepositoryTest.php
MockBlockManager.php in core/modules/system/tests/modules/plugin_test/src/Plugin/MockBlockManager.php
TestPageDisplayVariantSubscriber.php in core/modules/system/tests/modules/display_variant_test/src/EventSubscriber/TestPageDisplayVariantSubscriber.php

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