What is the LED in Audio port for? I recently attempted to install Ubuntu on may Late 2013 13" Mac Book Pro with Retina Display.

Under Linux I noticed a Red LED light inside the audio port. It looks like Ubuntu doesn't know how to handle it and activated it.

I have absolutely no idea what is that for, but I would really like to know.

Also is there any way to control it? : )
It is part of the the digital audio out built into that port. You can plug in a toslink cable instead of a 1/8th inch analog cable to get digital audio from your Mac Book. (via)

might not work in Ubuntu