$ git clone -n https://src.fedoraproject.org/rpms/R-errors.git /var/lib/mock/f45-build-6047-346/root/chroot_tmpdir/scmroot/R-errors
Cloning into '/var/lib/mock/f45-build-6047-346/root/chroot_tmpdir/scmroot/R-errors'...
$ git fetch origin 9ba494e8e8b4c1edce679445fced45284bf89d5c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-errors
 * [new ref]         9ba494e8e8b4c1edce679445fced45284bf89d5c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9ba494e Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild