There's a fork of gitbook v2 https://github.com/honkit/honkit https://github.com/honkit/honkit not sure how well maintained it is though MdBook is another goo

There's a fork of gitbook v2 https://github.com/honkit/honkit https://github.com/honkit/honkit not sure how well maintained it is though MdBook is another good one, as hip as it goes, written in Rust nonetheless :-)