19 files declare their use of UnknownExtensionException
- CategorizingPluginManagerTrait.php in core/
lib/ Drupal/ Core/ Plugin/ CategorizingPluginManagerTrait.php  - CategorizingPluginManagerTraitTest.php in core/
tests/ Drupal/ Tests/ Core/ Plugin/ CategorizingPluginManagerTraitTest.php  - DatabaseDriverList.php in core/
lib/ Drupal/ Core/ Extension/ DatabaseDriverList.php  - DatabaseTest.php in core/
tests/ Drupal/ Tests/ Core/ Database/ DatabaseTest.php  - DriverModuleMissingDependenciesTest.php in core/
tests/ Drupal/ Tests/ Core/ Database/ DriverModuleMissingDependenciesTest.php  - ExtensionList.php in core/
lib/ Drupal/ Core/ Extension/ ExtensionList.php  - ExtensionListTest.php in core/
tests/ Drupal/ Tests/ Core/ Extension/ ExtensionListTest.php  - ExtensionPathResolver.php in core/
lib/ Drupal/ Core/ Extension/ ExtensionPathResolver.php  - ExtensionPathResolverTest.php in core/
tests/ Drupal/ KernelTests/ Core/ Bootstrap/ ExtensionPathResolverTest.php  - install.core.inc in core/
includes/ install.core.inc  - API functions for installing Drupal.
 - ModuleHandler.php in core/
lib/ Drupal/ Core/ Extension/ ModuleHandler.php  - ModuleHandlerTest.php in core/
tests/ Drupal/ Tests/ Core/ Extension/ ModuleHandlerTest.php  - ModuleHandlerTest.php in core/
tests/ Drupal/ KernelTests/ Core/ Extension/ ModuleHandlerTest.php  - ReviewForm.php in core/
modules/ migrate_drupal_ui/ src/ Form/ ReviewForm.php  - ThemeHandler.php in core/
lib/ Drupal/ Core/ Extension/ ThemeHandler.php  - ThemeInstaller.php in core/
lib/ Drupal/ Core/ Extension/ ThemeInstaller.php  - ThemeInstallerTest.php in core/
tests/ Drupal/ KernelTests/ Core/ Theme/ ThemeInstallerTest.php  - update.inc in core/
includes/ update.inc  - Drupal database update API.
 - UrlConversionTest.php in core/
tests/ Drupal/ Tests/ Core/ Database/ UrlConversionTest.php  
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