They did build a browser; it may not be a very compliant or complete browser, or even a useful one, but neither was IE6!
I believe it was basically a broken, non-functioning wrapper around Servo internals. That’s what I’d expect from a high schooler who says “i wrote a web browser”, but not what I’d expect from a multi-billion dollar corporation.
My understanding is that it doesn't even compile if you clone the repo.
They didn't build a browser from scratch.
It didn't even compile, which makes me consider wether your comment is just ignorant or outright maliciously misleading