Whoops, I forgot about the other things I wanted to reply to :) > I wonder if it is worth it to fork an existing browser (Chromium, Firefox) for your purpose.

Whoops, I forgot about the other things I wanted to reply to :) > I wonder if it is worth it to fork an existing browser (Chromium, Firefox) for your purpose. But this is probably impossible to maintain and keep in sync with upstream. Yeah. People have suggested that in the past, but keeping up with e.g. Chromium is insane. When QtWebEngine updates their Chromium snapshot (a subset of the entire source) all couple of months, we're talking about millions of changed lines, and I've heard they need around a person-month every time to adjust their stable API to that. Also see: - https://chromium.googlesource.com/chromium/src.git/+log https://chromium.googlesource.com/chromium/src.git/+log - https://twitter.com/the_compiler/status/1330896103911264257 https://twitter.com/the_compiler/status/1330896103911264257 It's pretty much a commit all couple of minutes, almost around the clock. > I wonder whether there are other simple ways to hook into the browser. After all, you are in control of the OS, and you can inject some code. On MacOSX, there was actually some nice way to script things like this. But I think they restricted that very much now. I was actually wondering what someone could do via ChromeDriver: https://chromedriver.chromium.org/ https://chromedriver.chromium.org/ But I suppose the kind of UI/UX you could build with that would still be quite limited, perhaps even more so than what WebExtensions like Vimium or Tridactyl can do.