I’m not sure what actually uses it these days, but: the file
/etc/os-release on every Fedora Linux system used to point to Communicating and getting help - Fedora Project Wiki for
SUPPORT_URL. That’s a wiki page which needs quite a lot of work (and probably to be migrated to the new docs site). We’ve changed that to point to Ask Fedora instead.
After the new website redesign we might revisit and go back to some general page, but I figured this is the best for now.