$ git clone -n https://src.fedoraproject.org/rpms/R-spelling.git /var/lib/mock/f42-build-side-110318-58926582-6569309/root/chroot_tmpdir/scmroot/R-spelling
Cloning into '/var/lib/mock/f42-build-side-110318-58926582-6569309/root/chroot_tmpdir/scmroot/R-spelling'...
$ git fetch origin 7d5606bf4fef4b54b7f5e6ffd8c34a4634f4874c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-spelling
 * [new ref]         7d5606bf4fef4b54b7f5e6ffd8c34a4634f4874c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7d5606b R-maint-sig mass rebuild