$ git clone -n https://src.fedoraproject.org/rpms/R-rlecuyer.git /var/lib/mock/f45-build-6372-348/root/chroot_tmpdir/scmroot/R-rlecuyer
Cloning into '/var/lib/mock/f45-build-6372-348/root/chroot_tmpdir/scmroot/R-rlecuyer'...
$ git fetch origin 6b107108ad87ed011cb05697ef1314b5be77df9a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-rlecuyer
 * [new ref]         6b107108ad87ed011cb05697ef1314b5be77df9a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6b10710 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild