I'm also curious about this. When it was just a toy project it made sense to write everything from scratch. If it's supposed to eventually be usable by people, a hard fork of Chromium, or at least some Chromium components might make more sense. Having a browser that improves hackability and user freedom while working just as well as Chromium sounds like heaven to me. Anyways, I'm clueless about browser development so I might be completely wrong.