The IBM MQ and JMS bindings make references to the server URL scheme but on v3, the URL field on the server object is gone so that's not applicable. Maintainers should decide how to proceed in this case.
As an idea, the protocol field could be composed by two protocols as follows: file+ibmmq and http+ibmmq. This way, we make it clear it's a combination of two protocols. We're already doing this (informally) with MQTT over WebSocket or STOMP over Websocket where the protocol is ws+mqtt and ws+stomp respectively.
In any case, I think this is a good opportunity to clarify the meaning of the + symbol in the protocol field. For instance, why ws+mqtt and not mqtt+ws? What's the order and why? Etc.
This, or completely come up with another solution. I'm all ears.
cc @derberg @dalelane @smoya @char0n @rcoppen