POS Y
Empty. Used to trigger Pos Y out.
Essentially controlled by face angle Y in facial mocap tracking, but is directly tied to body Y in physics settings.
For some animation may need to set a lock toggle to turn POS Y on and off.
For example, when a character is in default standing still pose, having POS Y activate in actual facial mocap tracking makes full sense. But if they are walking, the stretch and squat motion shouldn't be there (unless that is specifically desired).