This docs site is itself an attested use case of the attested-delivery posture: the same supply-chain rigor the org preaches is applied to the site you are reading. The CI pipeline is fail-closed — an artifact that cannot be verified does not deploy.

• SHA-pinned actions, enforced. Every uses: is pinned to a full 40-char commit SHA. The central attested-delivery/.github pin-check reusable runs on the deploy workflow and fails closed on any tag/branch ref.
• Attested deploy (.github/workflows/deploy.yml): the published Pages artifact carries a SLSA build provenance attestation and a CycloneDX SBOM attestation, both keyless (Sigstore, via the run's OIDC id-token) and bound to the artifact's sha256 digest. A dedicated verify job re-checks both before the deploy job is allowed to run.

This is a static-file artifact (not a container image), so the SLSA backbone is actions/attest-build-provenance and the fail-closed verify runs gh attestation verify inline on the artifact file — the central reusable-verify-gates.yml verifies oci:// subjects by digest, not a caller-local file. There are no seam-signed gate verdicts here; the site ships the standard family only (provenance + SBOM).

You do not need this repo's permissions or secrets to check its work. From any workstation with the GitHub CLI authenticated (gh ≥ 2.49, which provides gh attestation). The commands below verify the latest deploy's artifact, which CI retains for 90 days:

# 1 · grab the exact artifact CI published (the Pages tarball, retained 90 days)
RUN_ID=$(gh run list --repo attested-delivery/docs \
  --workflow "Deploy docs to GitHub Pages" --status success \
  --limit 1 --json databaseId --jq '.[0].databaseId')
gh run download "$RUN_ID" --repo attested-delivery/docs \
  --name github-pages --dir ./_verify

# 2 · verify SLSA build provenance (bound to the artifact digest)
gh attestation verify ./_verify/artifact.tar \
  --repo attested-delivery/docs \
  --signer-workflow attested-delivery/docs/.github/workflows/deploy.yml \
  --predicate-type https://slsa.dev/provenance/v1

# 3 · verify the CycloneDX SBOM attestation
gh attestation verify ./_verify/artifact.tar \
  --repo attested-delivery/docs \
  --signer-workflow attested-delivery/docs/.github/workflows/deploy.yml \
  --predicate-type https://cyclonedx.org/bom

Each command exits non-zero on any failure. --repo pins where the build ran; --signer-workflow pins which workflow produced the attestation (the deploy workflow), which matters because this repo has more than one provenance-producing workflow (deploy.yml and dast.yml). Inspect the predicate body to read the recorded claim:

gh attestation verify ./_verify/artifact.tar \
  --repo attested-delivery/docs \
  --signer-workflow attested-delivery/docs/.github/workflows/deploy.yml \
  --predicate-type https://cyclonedx.org/bom --format json \
  | jq '.[0].verificationResult.statement.predicate | keys'

A successful verification proves the attestation is authentic and bound to the artifact. A signed attestation records that a gate ran and produced a verdict — read the predicate body for the verdict itself.

Open a private security advisory via the Security → Advisories tab on the repository, or start a thread in the org's discussions. Please do not file public issues for undisclosed vulnerabilities.