Where anatomically is the HEAD joint

Hi! 

The recommended way to get users head position for placing screens is via the AvatarAttachment component.

You can get the local head pose like so: 

// Function to get the pose of the user's head
fun getHeadPose(): Pose {
  val head =
      Query.where { has(AvatarAttachment.id) }
          .filter { isLocal() and by(AvatarAttachment.typeData).isEqualTo("head") }
          .eval()
          .first()
  return head.getComponent<Transform>().transform
}