Conjecture

The one asset class where provenance could be excludable is a holding, not a standard. An attestation cannot be retrofitted: once the originating moment has passed, material that was not attested at the time cannot be made verifiably so, which means an archive attested while attestation was possible is scarce in a way no open standard is. So the excludable provenance asset, if one exists, is a corpus of material whose origin is already attested and whose competitors cannot acquire it at any price, not the tooling that checks attestations. This is the only line of defence left to the retired half of C-R5V7X3FDFY, it is my own reasoning rather than a reading of any source, and two corpus searches (provenance/authenticity/verified-human-content, and attestation design) returned nothing addressing retrofit.

Narrative and audience