# External source check (CFD-READONLY-20260831)

Checked 2026-09-04 with `scripts/verify-external-sources.py` (GET, follow redirects, 25s timeout). None of these pages audited this fixture. Machine log: [`external-source-check-CFD-READONLY-20260831.json`](./external-source-check-CFD-READONLY-20260831.json).

| Source | Requested URL | Final URL | HTTP | Title SHA-256 | Note | Use |
|---|---|---|---|---|---|---|
| SP 800-53 Rev. 5 | https://csrc.nist.gov/pubs/sp/800/53/r5/upd1/final | https://csrc.nist.gov/pubs/sp/800/53/r5/upd1/final | 200 | fbdc404c0aef4a37 |  | Least privilege and security-control context |
| GRANT | https://www.postgresql.org/docs/current/sql-grant.html | https://www.postgresql.org/docs/current/sql-grant.html | 200 | 5af92afd4a7aae19 |  | Concrete SELECT and write privilege semantics |
| Assessing Data Reliability | https://www.gao.gov/products/gao-20-283g | https://www.gao.gov/products/gao-20-283g | 200 | 4b63162eff92e4ec |  | Accuracy, completeness, applicability, and risk-based review |
| AQuA Book | https://www.gov.uk/guidance/the-aqua-book | https://www.gov.uk/guidance/the-aqua-book | 200 | f618e2989914313f |  | Verification, validation, and fit-for-purpose assurance |
| ISO/IEC 11179 | https://www.iso.org/standard/53691.html | https://www.iso.org/standard/53691.html | 403 | 301dc171e5fa8c5f | http 403 | Metadata-registry context |
| RFC 4180 | https://www.ietf.org/rfc/rfc4180.txt | https://www.rfc-editor.org/rfc/rfc4180.txt | 200 | — |  | CSV interchange format |

Keep original requested URLs. Re-check at decision time.