Yes, Jupyterlab has a collaboration extension. I've spent the past month writing a HTTP+WebSocket proxy to be used with Jupyterlab for an ESA-adjacent company,

Yes, Jupyterlab has a collaboration extension. I've spent the past month writing a HTTP+WebSocket proxy to be used with Jupyterlab for an ESA-adjacent company, and spent a good deal of time trying to make the collaboration system work behind this proxy. That said, I don't think my contribution is at all related to this post.