$ git clone -n https://src.fedoraproject.org/rpms/R-maps.git /var/lib/mock/f45-build-6212-347/root/chroot_tmpdir/scmroot/R-maps
Cloning into '/var/lib/mock/f45-build-6212-347/root/chroot_tmpdir/scmroot/R-maps'...
$ git fetch origin 02a227cb1702449c708e50f03f41b9df8c40c4e4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-maps
 * [new ref]         02a227cb1702449c708e50f03f41b9df8c40c4e4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 02a227c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild