@stof it does care about the url. It uses the URL and namespace to determine the location of the file:

````php
$path = str_replace($extension->getNamespace(), str_replace('\\', '/', $extension->getXsdValidationBasePath()).'/', $items[$i + 1]);
````
https://github.com/symfony/DependencyInjection/blob/master/Loader/XmlFileLoader.php#L404-419