If you actually do the demo project thing, you'll find a .web directory, with all the next-js code. :)

F12 o Ctrl+U on most browsers

Most browsers are mobile so that won't work :)

I was hoping there is some technical explanation how the compilation step works (especially what do they do to event handlers) but their documentation is very light on details.

Firefox on android allows you to inspect source.

You need to prefix the url, ie.

    view-source:https://news.ycombinator.com/