I’ve been using Zen for the past couple days and it’s absolutely spectacular. I really really been enjoying it.

It claims to be a fork of Firefox but there’s still Firefox under the hood and you can tell. But I find that it runs significantly faster than Firefox standard. So who knows. The author seems to be making it as ambiguous as possible so I would think that it’s a soft fork that’s basically stock Firefox with a few minor changes and a new look.