14 files declare their use of ContextDefinition in Zircon Profile 8

ConditionTestDualUserTest.php in core/modules/system/tests/modules/condition_test/src/Tests/ConditionTestDualUserTest.php

Contains \Drupal\condition_test\Tests\ConditionTestDualUserTest.

ContextDefinitionTest.php in core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionTest.php

Contains \Drupal\Tests\Core\Plugin\Context\ContextDefinitionTest.

ContextHandlerTest.php in core/tests/Drupal/Tests/Core/Plugin/ContextHandlerTest.php

Contains \Drupal\Tests\Core\Plugin\ContextHandlerTest.

ContextPluginTest.php in core/modules/system/src/Tests/Plugin/ContextPluginTest.php

Contains \Drupal\system\Tests\Plugin\ContextPluginTest.

ContextTypedDataTest.php in core/tests/Drupal/Tests/Core/Plugin/Context/ContextTypedDataTest.php

Contains \Drupal\Tests\Core\Plugin\Context\ContextTypedDataTest.

CurrentLanguageContext.php in core/lib/Drupal/Core/Language/ContextProvider/CurrentLanguageContext.php

Contains \Drupal\Core\Language\ContextProvider\CurrentLanguageContext.

CurrentUserContext.php in core/modules/user/src/ContextProvider/CurrentUserContext.php

Contains \Drupal\user\ContextProvider\CurrentUserContext.

LazyContextRepositoryTest.php in core/tests/Drupal/Tests/Core/Plugin/Context/LazyContextRepositoryTest.php

Contains \Drupal\Tests\Core\Plugin\Context\LazyContextRepositoryTest.

MockBlockManager.php in core/modules/system/tests/modules/plugin_test/src/Plugin/MockBlockManager.php

Contains \Drupal\plugin_test\Plugin\MockBlockManager.

MultipleStaticContext.php in core/modules/block/tests/modules/block_test/src/ContextProvider/MultipleStaticContext.php

Contains \Drupal\block_test\ContextProvider\MultipleStaticContext.

NodeRouteContext.php in core/modules/node/src/ContextProvider/NodeRouteContext.php

Contains \Drupal\node\ContextProvider\NodeRouteContext.

OptionalContextConditionTest.php in core/modules/system/tests/modules/condition_test/src/Tests/OptionalContextConditionTest.php

Contains \Drupal\condition_test\Tests\OptionalContextConditionTest.

PluginTestBase.php in core/modules/system/src/Tests/Plugin/PluginTestBase.php

Contains \Drupal\system\Tests\Plugin\PluginTestBase.

TestPageDisplayVariantSubscriber.php in core/modules/system/tests/modules/display_variant_test/src/EventSubscriber/TestPageDisplayVariantSubscriber.php

Contains \Drupal\display_variant_test\EventSubscriber\TestPageDisplayVariantSubscriber.