The PhysBones document ( https://creators.vrchat.com/avatars/avatar-dynamics/physbones/ ) doesn't contain the following information that VRChat 2025.1.3 and SDK 3.8.0 introduced.
  • Execute in deterministic order
  • Maximum dependency depth is 8
  • ignoreOtherPhysBones option
The attached image is a capture of https://creators.vrchat.com/releases/release-3-8-0/