Azure attestation service could be an example of a confidential service where you can find the binary measurement. It is a good example as you need to trust that service to attest your confidential workloads. The problem obvs is that it is not open source but they have some samples to deal with their measurements.

https://github.com/Azure-Samples/microsoft-azure-attestation...

^^^ note the "Looks up for the MAA x509 extension;" part in the readme.

You can see their attestations in the JWT signing certificates.