$ git clone -n https://src.fedoraproject.org/rpms/regexp.git /var/lib/mock/f39-build-1557650-37299/root/chroot_tmpdir/scmroot/regexp
Cloning into '/var/lib/mock/f39-build-1557650-37299/root/chroot_tmpdir/scmroot/regexp'...
$ git fetch origin b63f85026ff88f406d316b7017ce49c06dae43b6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/regexp
 * [new ref]         b63f85026ff88f406d316b7017ce49c06dae43b6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b63f850 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild