fedora will also patch stuff from upstream to include in their distro. for better or worse arch will try to upstream the patch and if they don't like it just keep an older version around if they don't accept it
Both Fedora and Arch share that philosophy, though. There are very very few patches in Fedora compared to the Debian ecosystem - and often the only exceptions are support for features that in the process of being upstreamed, like Firefox' hardware acceleration support that was added by a Red Hat engineer.
