The amount of leverage you can get out of these paths is pretty incredible. The fundamental idea is really simple too if you boil it down to the absolute minimum essence...

The following 6 lines of javascript is all it takes to connect a hot pipe from server to client and dynamically invoke whatever is required.

  function StartApplication() {
    document.ApplicationSocket = new WebSocket(...);
    document.ApplicationSocket.onmessage = function (e) {
      return new Function('use strict";\n'+e.data)();
    }
  }

Anything that needs to talk back to the server would just send a message on the same socket.

This is pretty similar to how Blazor Server works, except we are able to bootstrap our client off <1kb of javascript+html source.