From the introduction: The Pathfinder Roleplaying Game is released under the Open Game License 1.0a, meaning the core rules that drive the Pathfinder RPG system are available to anyone to use for free under the terms of the OGL. This compendium of rules, charts, and tables contains all of the open rules in the system, and is provided for the use of the community of gamers and publishers working with the system. User summary: The formal Pathfinder Reference Document was a living, frequently updated corpus of information presented only in HTML format (various 3rd parties have produced PDF versions). On September 13, 2018, Paizo Publishing announced the Pathfinder Reference Document would no longer be updated; the document itself subsequently was handed off to a 3rd party interested in maintaining it as a web resource.