Its not actually emulating a real linux kernel. It implements its own "kernel" and elf loader: https://github.com/danoon2/Boxedwine/tree/master/source/kern... so this basically is light WSL w/ CPU emulation to run wine.

The project running on browser is not the main point. It can run standalone, and is mostly used to run old games that no longer work well on modern hardware / windows. Heck you can even use it on Linux.

I think the coolest part of the project is that it makes wine very portable though. Boxedwine seems like it could run on android as well for example.