Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T18:05:12+00:00	DMARC	—	VALID	`05b8824cc44a…`
2026-08-20T18:05:12+00:00	SPF	—	VALID	`1ff73dcee55c…`