All classes that implement LanguageConfigFactoryOverrideInterface in Drupal 9
- class \Drupal\language\Config\LanguageConfigFactoryOverride implements \Symfony\Component\EventDispatcher\EventSubscriberInterface, LanguageConfigFactoryOverrideInterface uses LanguageConfigCollectionNameTrait
- class \Drupal\language_hierarchy\Config\LanguageHierarchyConfigFactoryOverride