GNU IceCat
GNU IceCat, formerly known as GNU IceWeasel, is a free software rebranding of the Mozilla Firefox web browser distributed by the GNU Project. It is compatible with Linux, Windows, Android and OS X.
The GNU Project attempts to keep IceCat in synchronization with upstream development of Firefox while removing all trademarked artwork. It also maintains a large list of free software plugins. In addition, it features a few security features not found in the mainline Firefox browser.
History
Origins of the name
The Mozilla Corporation owns trademark to the Firefox name and denies the use of the name "Firefox" to unofficial builds that fall outside certain guidelines. Unless distributions use the binary files supplied by Mozilla, fall within the stated guidelines, or else have special permission, they must compile the Firefox source with a compile-time option enabled that creates binaries without the official branding of Firefox and related artwork, using either the built-in free artwork, or artwork provided at compile time.