I find the source code of the Netsurf browser really beautiful:

- https://netsurf-browser.org/

- https://source.netsurf-browser.org/netsurf.git/tree/

Including the sub projects, for instance:

- https://source.netsurf-browser.org/libcss.git/tree/

- https://source.netsurf-browser.org/libdom.git/tree/

It feels immediately obvious and understandable, which is quite impressive for a browser. Everything is well documented, well separated, the code is clean and seems simple, functions are small, etc. I am really impressed. I'd want to work on such code. I have never worked on it though, and I am not connected in any way to this project.