$ git clone -n https://src.fedoraproject.org/rpms/mfem.git /var/lib/mock/f41-build-1042228-18998/root/chroot_tmpdir/scmroot/mfem
Cloning into '/var/lib/mock/f41-build-1042228-18998/root/chroot_tmpdir/scmroot/mfem'...
$ git fetch origin 0d3bc3549bb7dc2fc4cbee6508a5808c1b813b15:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mfem
 * [new ref]         0d3bc3549bb7dc2fc4cbee6508a5808c1b813b15 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0d3bc35 fix sover