Met with JT and planned the next stages; I've now (today) implemented URL search string handling, except for one problem with window.onpopstate which needs to be handled; once that's working, we start some experimentation to see how portable active promise/fetch objects are (can we start a fetch in one process and add it to a promise.all in another process?), and if that works as we hope, we can rewrite the JavaScript to retrieve things with optimal efficiency.