..Think I read somewhere it's a saturation indicator, similar to the Mini which has an 'overload' led (lamp?) in the mixer section.
An original idea? err no.. Useful? well, nice to have a visual indication if saturation is used, or how any modulation you have routed there turns out. But you usually hear it just as well if not better. Hmm, seems like Access really want the kids to scream for this board.. Flashing logos..
Unless there's some unknown invention or function that would make use of this led. Would be nice if you could use it as a general indicator led, routing functions to it like you can do with the LFO led's in the C.