webvh_witness_proofs_unavailable· reason_code· applies to identity_resolution, auth_decisionparameters.witness declares a witness policy but the did-witness.json proofs file is unreachable, unparseable, or contains no entry for the versionId under evaluation. Unavailable evidence is not absent policy; the verifier MUST fail closed on high-risk paths rather than proceed as if no witnessing were required. See zh/identity/identity-did.md §3.4.1.