[Ur] unurlify

[Gergely Buday]

> No, client code can certainly do many useful things with sources.  However,
> in this case, you are probably using an RPC whose return type involves
> [source].  Currently such RPCs are not supported, but now I don't see any
> reason why I couldn't add support.  Was it your intention to return a
> [source] from an RPC?

Yes, I would like to return a record that includes some sources.

- Gergely