Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-21T23:14:47+00:00	DMARC	—	VALID	`a6d3e5df5fdb…`
2026-08-21T23:14:47+00:00	SPF	—	VALID	`2a6eefbaf268…`