One thing about Pathfinder and Starfinder is that Paizo posts the open source Reference Document online so anyone can check out the rules as well as fiddle with them and create their own bits for it. Paizo has announced that they're teaming up with Archives of Nethys who will now take over official curation of the documents.
From the announcement:
As a fan and a community advocate, you grow attachments to things you wouldn't have ever imagined you would. One of the projects I've gotten the opportunity to make my mark on at Paizo is neatly nestled into that fan/community/design challenge niche: the Pathfinder Reference Document. As it became obvious in this last year of architecting and laying out the plans for the future of paizo.com, and as the time increased between that "last updated" date and our resources began to shift course, a problem arose that we needed to solve: how do we provide our community a free, up-to-date online version of the rules for our games? Well, I finally get to share the answer with you all!
Paizo is pleased to announce that Blake Davis and the Archives of Nethys will be maintaining the Pathfinder and Starfinder Reference Documents!
As an official licensed partner, the Archives of Nethys includes setting-specific rules content as well as Open Game Content, so you'll be able to find the Golarion- and Pact Worlds–specific rules you're looking for quickly and easily.