When are XR prefabs used?

I see there is a Feminine and Feminine_XR animation avatars prefabs in the package, and the avatars I load seem to match up with the non “XR” ones. When are the XR ones used? I’m planning on using those prefabs to copy components to the runtime loaded avatar.

Hello and welcome to the forum!
The XR avatars are a new addition to our SDK as part of improving the experience with avatars in VR. We are adding Support for “fullbody-xr” body type (alpha): an XR-specific variant of full-body avatars with additional twist bones and a better hand rig.
This can be used if you are building an XR application or game. For now, it’s still in alpha. You can apply here for early access here: Ready Player Me XR-Optimized Avatars