$ git clone -n https://src.fedoraproject.org/rpms/giac.git /var/lib/mock/f41-build-857802-168220/root/chroot_tmpdir/scmroot/giac
Cloning into '/var/lib/mock/f41-build-857802-168220/root/chroot_tmpdir/scmroot/giac'...
$ git fetch origin 45b75e7fe278a2c796dd306b5484c1f1464ca6cd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/giac
 * [new ref]         45b75e7fe278a2c796dd306b5484c1f1464ca6cd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 45b75e7 Rebuild for pari 2.17.0