From publisher blurb:
This new Advanced Knights of the All Mind Judges Book combines various home brew rules adopted from a variety of influences with the Open Gaming License System Reference Documents. Primarily this work is based on v.5.1, but there are also small amounts of discrete rules from v.3.5.
Magic items descriptions and beastiary are included within this work.
The tome is much less a "hack" per se than subtle departures from what a player would obtain from purchasing the mainstream version of rules that would include v.5.1 or downloading the free version of v.5.1 rules. Ha, of course one would miss the art.
Also included is a very simple, 70's-style campaign characters record sheet for judges.