As much as I dislike Mathfinder... sorry, Pathfinder, I give props to Paizo for doing the right thing: "The Open RPG Creative license is envisioned as a broader framework, along the lines of GNU or Creative Commons, in which companies may independently deposit their own System Reference Documents. In that sense it is not tied to a single system or small set of systems (and, importantly, is not owned by a single RPG publisher)."
Extra points for mentioning GNU. #ttrpg
https://gizmodo.com/paizo-universal-rpg-license-interview-jim-butler-1849986745