We first heard about Tizen, the Linux-based open source software platform, back in September when it rose from the ashes of MeeGo. The project has now reached an important milestone with the official release of the Tizen 1.0 Larkspur SDK and source code. Developers have been able to take a peek at preliminary versions of both since January, but the 1.0 release includes a new browser-based simulator for running and debugging web apps and an improved emulator. The source code itself has incorporated enhanced HTML5 support and added new location services functionality. Of course, it's unclear just how widely Tizen will be adopted, despite the long list of industry heavyweights behind the project — but we imagine we'll get some indication during Tizen's developer conference next month. In the meantime, if you'd like to dig in for yourself, Tizen is available for download now.