Just what the hell is MC5?
It seems that just about everyone you could ask - or dare ask - would give you a different response. The corporate types would probably tell you it doesn't exist. Those on the streets would spout some form of bullshit conspiracy theory, borne more out of booze or drug use than rational thought.
The NCPD? Don't even bother. They'd much sooner haul you into a cell or shoot you. And with Reza being the recluse he is, the chances of him issuing a statement about it are slimmer than the hookers in Pepper Park.
If anyone's going to have even a vague hope of knowing what it is, it'll be the hackers. You find a hacker good enough - or crazy enough - and there's nothing you can't find out. Provided you've got enough credits to make it worth the risk...