Authentication history

Immutable persisted observations.

Observed	Signal	Selector	Verdict	Fingerprint
2026-08-16T20:28:16+00:00	DMARC	—	VALID	`3d3e4a146a8c…`
2026-08-16T20:28:16+00:00	SPF	—	VALID	`175efbb1f626…`