Anybody remember TermKit[0]? This was my first thought when I saw "JS/HTML/CSS Terminal". It was built on WebKit (five years ago, before the everything-in-JS craze really began) and had a lot of really promising features like smart MIME-type support... and then development sort of stopped. I'd love to see the concept revisited with present-day technologies and platforms. [0]: https://acko.net/blog/on-termkit/
Heh yes. There was also a mozilla XUL based terminal many years ago - can't remember the name though.
The only article about is that I've ever found or read is this one: