$ git clone -n https://src.fedoraproject.org/rpms/R-mlbench.git /var/lib/mock/f45-build-6241-347/root/chroot_tmpdir/scmroot/R-mlbench
Cloning into '/var/lib/mock/f45-build-6241-347/root/chroot_tmpdir/scmroot/R-mlbench'...
$ git fetch origin ff978969d78b59ba53bb6b5299855bc09309877b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-mlbench
 * [new ref]         ff978969d78b59ba53bb6b5299855bc09309877b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ff97896 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild