$ git clone -n https://src.fedoraproject.org/rpms/krdp.git /var/lib/mock/f42-build-side-1-3577602-46813/root/chroot_tmpdir/scmroot/krdp
Cloning into '/var/lib/mock/f42-build-side-1-3577602-46813/root/chroot_tmpdir/scmroot/krdp'...
$ git fetch origin 307b91974d08a8f705e029a32a09ffc7f2056e57:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/krdp
 * [new ref]         307b91974d08a8f705e029a32a09ffc7f2056e57 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 307b919 6.4.1