I’m one of the maintainers of the Mac build of GIMP, so I spend a lot of time on gitlab.gnome.org working out whether an upstream fix has shipped in a release. Until it has, I carry a patch, so I’m forever checking.
I built released to stop doing it by hand. Paste a gitlab.gnome.org commit or MR and it gives you the first release tag that contains it, plus a permalink you can drop into an issue. It works across GNOME projects (and GitHub, and other GitLab hosts). Free, MIT.
Here’s one I’m tracking right now, a GTK focus fix that landed on gtk-3-24 but isn’t in a release yet:
And one that has shipped, so you can see the answer:
Sharing in case it helps anyone else doing triage or packaging. Happy to fix anything that misbehaves or add projects that don’t resolve.
There’s also a CLI in case you want to run locally.