It allows you to switch Headphone Mux using amuxer between DAC and Line In.
In DAC mode (default value), the sound from Organelle (such as synthesizers, etc.) is played through the headphone port.
In Line-In mode, sound from Line-In is played through the headphone port.
This can be useful for use with OTC – the sound is input to the input for visualization and redirected to the headphone port.
After a reboot, the current value is reset to the DAC.