PrependExtensionInterface

class \Symfony\Component\DependencyInjection\Extension\AbstractExtension extends \Symfony\Component\DependencyInjection\Extension\Extension implements \Symfony\Component\DependencyInjection\Extension\ConfigurableExtensionInterface, \Symfony\Component\DependencyInjection\Extension\PrependExtensionInterface uses \Symfony\Component\DependencyInjection\Extension\ExtensionTrait
class \Symfony\Component\HttpKernel\Bundle\BundleExtension extends \Symfony\Component\DependencyInjection\Extension\Extension implements \Symfony\Component\DependencyInjection\Extension\PrependExtensionInterface uses \Symfony\Component\DependencyInjection\Extension\ExtensionTrait