SoListenerOrientationElement(3) on Linux
The text de5447e1c213, as Debian 6.0 (Squeeze) shipped it.
The SoListenerOrientationElement holds the orientation of the current listener. This orientation is set by SoListener nodes and SoCamera Nodes during audio rendering. When a SoListener is visited by the SoAudioRenderAction, it will add a new SoListenerOrientationElement to the state, holding it's orientation and with the setbylistener flag set. When a SoCamera is visited by SoAudioRenderAction, it will add a new SoListenerOrientationElement only if there are no previous elements with the setbylistener flag set.