The "Symfony\Component\HttpKernel\DependencyInjection\Extension" class is considered internal since Symfony 7.1, to be deprecated in 8.1; use Symfony\Component\DependencyInjection\Extension\Extension instead. It may change without further notice. You should not use it from "FOS\JsRoutingBundle\DependencyInjection\FOSJsRoutingExtension".
Changing the extension base class would only cause the drop of getXsdValidationBasePath and getNamespace, which are easily overwritten (see \Symfony\Component\DependencyInjection\Extension\Extension).
Changing the extension base class would only cause the drop of
getXsdValidationBasePathandgetNamespace, which are easily overwritten (see\Symfony\Component\DependencyInjection\Extension\Extension).