25 files declare their use of Extension in Zircon Profile 8

config_translation_test.module in core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.module

Configuration Translation Test module.

FieldDefinitionIntegrityTest.php in core/modules/field/src/Tests/FieldDefinitionIntegrityTest.php

Contains \Drupal\field\Tests\FieldDefinitionIntegrityTest.

InstallStorage.php in core/lib/Drupal/Core/Config/InstallStorage.php

Contains \Drupal\Core\Config\InstallStorage.

locale_test.module in core/modules/locale/tests/modules/locale_test/locale_test.module

Simulate a custom module with a local po file.

locale_test_development_release.module in core/modules/locale/tests/modules/locale_test_development_release/locale_test_development_release.module

Simulate a Drupal version.

locale_test_translate.module in core/modules/locale/tests/modules/locale_test_translate/locale_test_translate.module

Simulates a custom module with a local po file.

ModuleHandlerTest.php in core/tests/Drupal/Tests/Core/Extension/ModuleHandlerTest.php

Contains \Drupal\Tests\Core\Extension\ModuleHandlerTest.

ModulesListForm.php in core/modules/system/src/Form/ModulesListForm.php

Contains \Drupal\system\Form\ModulesListForm.

module_required_test.module in core/modules/system/tests/modules/module_required_test/module_required_test.module

module_test.module in core/modules/system/tests/modules/module_test/module_test.module

nyan_cat.engine in core/modules/system/tests/themes/engines/nyan_cat/nyan_cat.engine

Handles integration of Nyan cat templates because we love kittens.

PermissionHandlerTest.php in core/modules/user/tests/src/Unit/PermissionHandlerTest.php

Contains \Drupal\Tests\user\Unit\PermissionHandlerTest.

ProjectInfo.php in core/lib/Drupal/Core/Utility/ProjectInfo.php

Contains \Drupal\Core\Utility\ProjectInfo.

system.module in core/modules/system/system.module

Configuration system that lets administrators modify the workings of the site.

SystemLocalTasksTest.php in core/modules/system/tests/src/Unit/Menu/SystemLocalTasksTest.php

Contains \Drupal\Tests\system\Unit\Menu\SystemLocalTasksTest.

system_test.module in core/modules/system/tests/modules/system_test/system_test.module

TestRunnerKernel.php in core/lib/Drupal/Core/Test/TestRunnerKernel.php

Contains \Drupal\Core\Test\TestRunnerKernel.

ThemeHandlerTest.php in core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php

Contains \Drupal\Tests\Core\Extension\ThemeHandlerTest.

ThemeInitialization.php in core/lib/Drupal/Core/Theme/ThemeInitialization.php

Contains \Drupal\Core\Theme\ThemeInitialization.

ThemeInitializationInterface.php in core/lib/Drupal/Core/Theme/ThemeInitializationInterface.php

Contains \Drupal\Core\Theme\ThemeInitializationInterface.

theme_page_test.module in core/modules/system/tests/modules/theme_page_test/theme_page_test.module

theme_test.module in core/modules/system/tests/modules/theme_test/theme_test.module

twig.engine in core/themes/engines/twig/twig.engine

Handles integration of Twig templates with the Drupal theme system.

UpdateRegistry.php in core/lib/Drupal/Core/Update/UpdateRegistry.php

Contains \Drupal\Core\Update\UpdateRegistry.

update_test.module in core/modules/update/tests/modules/update_test/update_test.module

Module for testing Update Manager functionality.