$ git clone -n https://src.fedoraproject.org/rpms/ghc-optparse-simple.git /var/lib/mock/f39-build-1918688-42935/root/chroot_tmpdir/scmroot/ghc-optparse-simple
Cloning into '/var/lib/mock/f39-build-1918688-42935/root/chroot_tmpdir/scmroot/ghc-optparse-simple'...
$ git fetch origin b3c5b8dc9273748d6af34348cf0e1b489081fb89:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-optparse-simple
 * [new ref]         b3c5b8dc9273748d6af34348cf0e1b489081fb89 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b3c5b8d githash-0.1.7.0