Great post. At the moment I'm really interested in Andreas Kling's Ladybird web browser [0], LibWeb and the videos he live streams [1] of development. It's been a long time since anyone's built a browser for fun instead of profit (don't get me started on what Mozilla has turned into). A lot of people will say it's impossible but at the start nobody imagined Linux would become what it is today. Either way it's extremely fascinating and educating for me to watch him build the thing, see how his thought process works, how he debugs it by just picking random websites and fixing whatever doesn't work, etc.
[0] https://github.com/SerenityOS/ladybird
[1] https://www.youtube.com/watch?v=k2LuvCAUvW0