$ git clone -n https://src.fedoraproject.org/rpms/R-mnormt.git /var/lib/mock/f42-build-side-1-3500325-45970/root/chroot_tmpdir/scmroot/R-mnormt
Cloning into '/var/lib/mock/f42-build-side-1-3500325-45970/root/chroot_tmpdir/scmroot/R-mnormt'...
$ git fetch origin 3585397e7d46b882072029d6ebb82f59b9644b98:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-mnormt
 * [new ref]         3585397e7d46b882072029d6ebb82f59b9644b98 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3585397 R-maint-sig mass rebuild