Swiftfox is an optimized build of Mozilla Firefox. Swiftfox has builds for both AMD and Intel processors. The 2.0.0.7 release is based on Firefox 2.0.0.7. The trunk is the most cutting edge of all the builds and is where Firefox 3 is being developed. Branch builds are built from a code base that has been tested much more than the trunk and therefore should be considered to be more stable. Swiftfox 2.0.0.8pre is from the 1.8 branch which is where Mozilla tests security patches and other minor fixes before they release the next Firefox update. If you want your security patches as soon as possible and require a browser built from a stable code base this build is perfect for you.....(free).....