$ git clone -n https://src.fedoraproject.org/rpms/ghc-with-location.git /var/lib/mock/f39-build-1965910-43294/root/chroot_tmpdir/scmroot/ghc-with-location
Cloning into '/var/lib/mock/f39-build-1965910-43294/root/chroot_tmpdir/scmroot/ghc-with-location'...
$ git fetch origin 786e091d2ac61e359911a1e1357972ccb2f5b902:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-with-location
 * [new ref]         786e091d2ac61e359911a1e1357972ccb2f5b902 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 786e091 bump release