In the spec, "For example, if the gamepad attribute is not null the profile identifies the mapping of the buttons and axes of the attribute of the XRInputSource." Does this imply that the profiles list should be empty for an XRInputSource that does not have a gamepad? If not, then some text clarifying that it's still useful even without a gamepad would be helpful.

Also, should the profiles list be empty for transient input sources? For example, WMR voice commands are transient input sources that can occur in immersive sessions.