Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-18T06:57:58+00:00	DMARC	—	VALID	`d473b802974f…`
2026-08-18T06:57:58+00:00	SPF	—	VALID	`c6f3a6738cb8…`