User summary:
Numerous Judges Guild products were marketed as "A Judges Guild Universal Fantasy Supplement". These products were system agnostic and intended to be usable with any then-current fantasy roleplaying game system. To support rapid, easy, and consistent use across a variety of systems, Judges Guild developed and used a "Universal Fantasy" format of development and presentation.
Generally speaking, this format emphasized the design commonalities of early versions of Dungeons & Dragons, RuneQuest, and Tunnels & Trolls, while minimizing their distinctiveness. The resulting presentation may appear at first to be a new or unique game system, but it never was intended to be usable on its own. The format developed through time, but even in its final state it was not a complete game system. Rather, it is a comprehensive notation system used to present scenarios and sources in a standardized, but system agnostic, fantasy format.
In 2010, Judges Guild published this "final state" document that presents the "Universal Format"; it is made available as a free download.