Mozilla launched its first Firefox OS Simulator late last year, letting developers test out apps on the new platform even though the software was still very much in development. It only makes sense, then, that a new version would surface following the mobile operating system's official unveiling at Mobile World Congress 2013. Like versions 1.0 and 2.0, Firefox OS Simulator 3.0 runs as an extension in Mozilla's browser and is available on Linux, Windows and OS X. The new preview adds several features, including Push to Device, which brings over apps installed on the OS Simulator to a Firefox OS device provided it's connected via USB. Rotation simulation and an updated version of the software's Gaia interface are also on board. To give the Simulator a go, head to Mozilla's FTP server, where you'll find it under the working name r2d2b2g. Click through to source links for the full installation directions.