Originally Posted by KillerRabbit
This is a part of the SRD that I don't understand. Pathfinder pays WotC something but, reading the SRD, I can't figure out why it does.

Could be this part on the checklist:

* I want my content considered for inclusion in digital games

https://dnd.wizards.com/articles/features/systems-reference-document-srd

Correct me please if I'm wrong, but Pathfinder was based on the 3.5 SRD, which was complete enough to look like D&D still, and Pathfinder can now stand alone.

The 5.1, is very bare bones.