$ git clone -n https://src.fedoraproject.org/rpms/loupe.git /var/lib/mock/f40-build-2664777-67074/root/chroot_tmpdir/scmroot/loupe
Cloning into '/var/lib/mock/f40-build-2664777-67074/root/chroot_tmpdir/scmroot/loupe'...
$ git fetch origin b4bfd6c7996cce394e0e130bb070024dfe96123b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/loupe
 * [new ref]         b4bfd6c7996cce394e0e130bb070024dfe96123b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b4bfd6c Update to 46.0