$ git clone -n https://src.fedoraproject.org/rpms/mu.git /var/lib/mock/f39-build-1847051-42131/root/chroot_tmpdir/scmroot/mu
Cloning into '/var/lib/mock/f39-build-1847051-42131/root/chroot_tmpdir/scmroot/mu'...
$ git fetch origin fa240098b123c4958a11b5bfc8cc68daa3a96c66:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mu
 * [new ref]         fa240098b123c4958a11b5bfc8cc68daa3a96c66 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fa24009 Backport upstream patch needed for compatibility with Python 3.12