Chimera 0.4 is a browser for MacOS X built on top of Mozilla…
The cross-platform UI will be replaced with native Cocoa widgetry (such as customizable toolbars and a drawer for the sidebar). The plan is to produce only a browser (no other apps!), and to keep the UI as simple and as clean as possible.
I’ve always thought open source development doesn’t lend itself to quality UI design. But in this case they can draw from 1) years of web browser conventions, and 2) the MacOS X human interface guidelines. I’m looking forward to the results.