Welcome to the official Libretro/RetroArch Documentation!Link
RetroArch is a frontend for emulators, game engines and media players.
It enables you to run classic games on a wide range of computers and consoles through its slick graphical interface. Settings are also unified so configuration is done once and for all. RetroArch has advanced features like shaders, netplay, rewinding, and more!
libretro is a simple backend API that allows for the creation of games and emulators.
It aims for emulators, game engines and media players to be run through a unified GUI. The libretro system powers the RetroArch application.
Which platforms are RetroArch available for?Link
RetroArch runs and is supported on GNU/Linux, BSD, Windows, Mac OSX (PPC/Intel), Haiku, PlayStation 3, Playstation Vita, Playstation Portable, Xbox 360, Xbox 1, Raspberry Pi, Nintendo GameCube, Nintendo Wii, Nintendo Wii U, Nintendo 3DS, Android, iOS, Open Pandora, and Blackberry.
What is the license for this?Link
libretro is released under the MIT license. RetroArch is released under the GNU GPLv3. The cores are usually released with the same license as the originating projects.
What emulators and games are currently supported?Link
You can see a list sorted by hardware maker under For Users > Core Documentation