Is it canon? Is it AU? In this group, it can be both!
This is a group for stories about "canon alternative universes": Equestria Girls and the Mirrorverse in the IDW comic. Other canon alternative universes also have a folder, in which you can place fics that belong to the Power Ponies verse, the bookverse, Aquastria, etc..
This isn't for other alternate universes: the Lunaverse or the Winningverse, for example, or for crossover fics set in another (non-Pony) universe. It's just for fics based on alternate universes from official sources.