Doesn't "source no longer available only concerns projects that have migrated to a nonfree license? This is a problem on F-droid, as the app you're installing

Doesn't "source no longer available only concerns projects that have migrated to a nonfree license? This is a problem on F-droid, as the app you're installing will not get updates, and are out-of-sync with upstream. I was pretty sure F-droid archived the source tarball, but i can't find it now. Disappearing sources are also an issue, as it has every disadvantage proprietary software has, with none of the upsides. It's much harder to patch in case it is needed, for instance. And hard to tell if someone tampered with the binary archives, I guess? (IIRC, the hash in Nix is based on the configuration, not the resulting binary).