From the introduction:
Welcome to the first round of playtesting for the upcoming Advanced Race Guide. This book will be jam- packed with new character options based on races in Pathfinder, from new spells and magic items for the core races from the Pathfinder Roleplaying Game Core Rulebook, to new archetypes and feats for 0-Hit Die races from Bestiary 1, Bestiary 2, and Bestiary 3. In this round we’re playtesting the race builder—a way GMs and players (the latter with GM oversight) can create new playable races for any Pathfinder campaign. While still a work in progress, the framework of this system is fleshed out enough for you to start building new races and let us know both how the system works and what you can create with it. So take a read, build some races, play those races in one-shot games or your home campaign, and give us feedback on what you think. We’re looking forward to reading your playtest and the outcome of your new race builds!