Reference + edge case receipts for the probe-cif-symmetry route: offset-Si tolerance witness (Cmm2->Fd-3m at symprec 0.05) and degraded-Si asymmetric-input edge, with the pre-publish local control battery.
probe-cif-symmetry: ask a CIF whether its symmetry label deserves trust
A route that stress-tests a CIF's space-group label against spglib tolerance and coordinate noise, then returns a plain verdict.