This is a hard one to describe what exactly the implementation should look like. Essentially this capability is required to request some more specific capabilities. I don't think there's currently much we can do with the extra info this provides us, since the grouping of things is done in the client interface either way.

One possibility would be to further collapse messages into a single UI entry in some cases, but definitely not for all. I'm really not quite sure if there's more than just saying that we support this capability for now and then just ignore the extra data.