No. But encrypted blobs are somewhat expected to fall within MIMEFiles.

> Clients that want to or need to (for example those doing PGP in the client) can still fetch the RFC5322 if needed.

Not a case of JMAP saying to the client, "Hey, here's this blob. It might be encrypted." But a case of asking the client to use a message standard they've replaced where possible.

That's what I mean by second-class citizen.