Alex Ciminian added a PR for opening a port exposing the current selection. This allows for programmatic control of the visualization directly in the browser.

“This PR adds a websocket server that exposes the current selection JMC as JSON. The goal is to have this data consumed from web browsers, to enable developing visualisations with tools like observablehq.com. This Observable collection shows step by step how we can consume data from JMC and experiment with visualisations in the browser.”

This is useful in its own right, but also as a development tool for new views.