I'll take a look! I've not gone deep into the nuts and bolts, but ATProtocol lexicons have a mix of open standards in the bucket: JSON Schema, OpenAPI, IETF standard (RFC something ) for binary data serialisation, W3C standard DIDs, OAuth 2.0 (also RFC something) and of course DNS. Probably leaving out a few. For what lexicons specifically do (i.e. facilitate interop in Nostr/ATProto/Farcaster-ish environments), I don't think there's anything off the shelf that wouldn't have to be overly shoehorned anyway. What would it be?