As discussed with Fintan in the review of patch 4bce378 on Zulip in the context of work on rad cob show:

Fintan wrote:

The other thing I’m realising is that rad cob was meant to be general purpose, i.e. support any type of COB, but now there’s no way of looking at a non-Radicle COB in JSON. So, if this is plumbing we might want to come up with a way for evaluating custom COBs via some shell to a process, for example.

Lorenz wrote:

While implementing I also was asking myself whether there is something like a “registry” for COBs, that tells me “use this thing to evaluate COBs of that type”. IMO this “registry” component (name to be bikeshed) is a precondition to evaluating ‘arbitrary’ COBs. I mean, if you don’t even know where the code for evaluation lives, how are you gonna evaluate? :)