Controller classes have been changed to final

[henrypenny]

I'm trying to update an older Kunstmaan CMS site to Symfony 5. There are a lot of controllers in the project that extend the Kunstmaan Controller classes. I'm finding that many of them are now final This is making my upgrade process incredibly frustrating. What is the benefit of these classes being final? This is a big BC break for me. I'm having to copy and paste code out of the kunstmaan classes into user land controllers.

e.g.: final class SettingsController extends AbstractController