The System Reference Document (SRD) is a set of reference role playing game mechanics licensed under the Open Game License by Wizards of the Coast (or WotC) and based upon their Dungeons and Dragons role-playing game. The SRD forms the basis of WotC's various d20 System role-playing games, including the d20 System itself, d20 Modern and d20 Future. The SRD is also the basis for role-playing games published by companies other than WotC; these include Mutants & Masterminds, Arcana Evolved, Labyrinth Lord, and OSRIC, among others. Some other game systems (such as FATE) have also released their own mechanics under OGL-licensed "System Reference Documents" of their own; however, this article discusses specifically the d20 System SRD.