$ git clone -n https://src.fedoraproject.org/rpms/mfem.git /var/lib/mock/f38-build-side-42-init-devel-1198971-30630/root/chroot_tmpdir/scmroot/mfem
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1198971-30630/root/chroot_tmpdir/scmroot/mfem'...
$ git fetch origin 6fa5ebd10c5f6b16d18ffd44b635b869904097af:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mfem
 * [new ref]         6fa5ebd10c5f6b16d18ffd44b635b869904097af -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6fa5ebd remove i686 architecture