I wanted to share the news that during the ipywidgets sprint in Paris Jason Grout and me worked on an extension to (dynamically) load other extensions – no more rebuilding for developing JLab extensions! A simple refresh of the page will soon be enough!
The repository is here: https://github.com/wolfv/jupyterlab-dynext
And you can find some more information and our future ideas here: https://wolfv.github.io/posts/2020/01/19/ipywidgets-writeup.html
Curious to hear what other people think!