$ git clone -n https://src.fedoraproject.org/rpms/R-msm.git /var/lib/mock/f45-build-6268-347/root/chroot_tmpdir/scmroot/R-msm
Cloning into '/var/lib/mock/f45-build-6268-347/root/chroot_tmpdir/scmroot/R-msm'...
$ git fetch origin adbd3a634c7d39823e98a82a4ad8dedccbc69d49:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-msm
 * [new ref]         adbd3a634c7d39823e98a82a4ad8dedccbc69d49 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at adbd3a6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild