samueldr: to me the larger issue is that it's unclear whether a build problem is a known issue or not. E.g. I observe that `nixos-rebuild switch` takes > 10 hours on 20.09 because things aren't fetched from cache, but I have no idea if that's a known problem or if I'm the first to notice. That makes you feel uncertain, so most users would probably not bother and just wait it out, and nobody knows if somebody else already picked upt the task of working on it. If we had a defined place where those things are discussed, I could easily know if I'm the first one to notice, or subscribe to the issue if not. This could also be the nixpkgs issue tracker with a label, as long as it's clear where the place is.