ROOT / HANDLE_ATTESTATION / SUB_ATTESTATION identify the
attestation-chain level; SESSION identifies the session token or
session-constraint layer; FORMAT identifies structural/usage
failures detected before any signature or trust material is consulted
(token shape, field validation, derivation-tree and lifecycle rules).
The layer that produced an AttestationError.
ROOT/HANDLE_ATTESTATION/SUB_ATTESTATIONidentify the attestation-chain level;SESSIONidentifies the session token or session-constraint layer;FORMATidentifies structural/usage failures detected before any signature or trust material is consulted (token shape, field validation, derivation-tree and lifecycle rules).