$ git clone -n https://src.fedoraproject.org/rpms/R-disposables.git /var/lib/mock/f45-build-6078-346/root/chroot_tmpdir/scmroot/R-disposables
Cloning into '/var/lib/mock/f45-build-6078-346/root/chroot_tmpdir/scmroot/R-disposables'...
$ git fetch origin 8144ced0f36344f86624b097983e78700112668e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-disposables
 * [new ref]         8144ced0f36344f86624b097983e78700112668e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8144ced Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild