Interesting! Looks like someone has wirewrapped a circuit out of what seem like discreet logic chips, there's even some LED's as indicators there. Doesn't look like it's connected to the main bus, just to some connector on the back panel. SCSI maybe (did the NEXT have a 25pin SCSI connector?).

Some more hi-res pictures of the chips might give us a better idea of what is does (or should I say did ).