Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-20T05:35:10+00:00	DMARC	—	VALID	`93af68f84b7d…`
2026-08-20T05:35:10+00:00	SPF	—	VALID	`1efd4da949f1…`