Hi,
For "Register", we only provide the feature of facial tracking extension so that developers can enable it to get facial tracking data via OpenXR interface if the facial kit is connected on VIVE Focus 3.
As to the 90-degree rotated to the hand tracking, could I confirm again that you are using OpenVR instead OpenXR, right?
The issue should not be there when you are using XR_EXT_hand_tracking since we have also tested some OpenXR content.
And if you are using OpenVR, I guess you are retrieving hand skeleton data with EVRSkeletalMotionRange set to VRSkeletalMotionRange_WithController, right?