[Supply chain] Request signed provenance bundle and SBOM for Postgres image digest

[Alamrob]

Hello maintainers,

We are evaluating the following public Supabase Postgres image for a controlled technical pilot:

public.ecr.aws/supabase/postgres@sha256:42088c86593e0d4f47b2b2bd3c964cee31a1bbc8e560619fd3e84e5fdd973f6d

The OCI index references these architecture-specific image manifests:

• amd64: sha256:a89d080bddb7a99104a01db136702c16dc5748752d2a9df57c315703346cc684
• arm64: sha256:85ee233d90b52b3c012e3de2214fa7b4e8cc4048fd18c5f99618cecc0eec6898

Could you please provide the public location of, or access instructions for:

1. A signed provenance/attestation bundle bound to the exact index or architecture-specific image manifests.
2. The corresponding SBOM, also bound to the relevant digest(s).
3. Public verification material and the expected producer/signer identity.
4. Any applicable trust-policy, key/certificate lifecycle, or revocation documentation needed to verify the evidence correctly.

We found the OCI-attached in-toto/SLSA statement payloads, but they did not include a signed envelope, certificate, or verification bundle. Authenticated queries to the GitHub repository- and organization-level artifact-attestation endpoints returned 404 for the three digests above. We are not treating those responses as proof that attestations do not exist.

If these artifacts live elsewhere or require a specific public permission/API route, please let us know.

We are not requesting secrets, private keys, account credentials, or access to private infrastructure.

Thank you.