Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T23:22:50+00:00	DMARC	—	VALID	`572de0ddbf5c…`
2026-08-16T23:22:50+00:00	SPF	—	VALID	`8128c740e707…`