Firefox for mobile (codenamed Fennec), or (Mozilla) Firefox for Android, is the build of the Mozilla Firefox web browser for devices such as smartphones and tablet computers.Firefox for mobile uses the same Gecko layout engine as Mozilla Firefox. For example, version 1.0 used the same engine as Firefox 3.6, and the following release, 4.0, shared core code with Firefox 4.0. Its features include HTML5 support, Firefox Sync, add-ons support and tabbed browsing.