I'd love to get a better look at it, what video was this from?
There is definitely enough space inside the housing for a few connectors on that side of the unit. Those look like locking connectors, Ethercon, XLR; could be a few things. The headphone(line out) output is on that back corner as well, so they may have just made a secondary audio output. I can say that it isn't an add on from AVIOM.
This screenshot is from a dutch radioshow. All live performences at the 3FM station are recorded at this 'playground'. Do a search on youtube for "3fm" or "Giel" (this particular show), and you'll find a lot of videos.
They have an LS9 in the controlbooth, which is outputting a few submixes to the aviom systems. Makes for easy setting up, which is nice if you're in there for a morning show:-)
Over here in Holland I've seen a lot of aviom systems with these connectors on the side, so many that for a long time I actually thought they were made like this. I Think the connectors are the standard Neutrik RJ45 connectors, built in a housing that fits the Aviom. There are only ethercon connectors on there, no extra audio. They rigged a headphone splitter below the panel to accomodate extra cans.....
I do not know where these connectors come from, I'll look into it. Musn't be too hard to find, since they are quite common over here.....