It seems to be more of an experiment than an actual language. There's no implementation nor a concrete plan to make one. The rationale is: programming languages are developed mostly through their implementation, what kind of Lisp do we get when we skip the implementation part and all the constraints that come with it?

Why do this? Why prolong the formal phase? One answer is that it's
an interesting exercise in itself to see where the axiomatic approach
leads. If computers were as powerful as we wanted, what would
languages look like?