It's not quite a match to what you're looking for, but I think Nyxt's long-term plan is to build something similar (essentially, be a Common Lisp environment f

It's not quite a match to what you're looking for, but I think Nyxt's long-term plan is to build something similar (essentially, be a Common Lisp environment for a browser window in the same way that Emacs is an lisp environment for a text editor). https://nyxt.atlas.engineer/ https://nyxt.atlas.engineer/