Games aren't the only thing that can exist in prototype form - companies need to test and show off their hardware stuff, too!
Essentially, this is the same as the release Miracle, sans plastic cover and cool manual. The rear of the unit has the connections all set up, and the cart's contents seem more or less the same as the one packed in with the unit.
Still, without a doubt the true allure of protos - the nakedness of the hardware, the forbidden peek into the hardware lab, the curvaceousness of the heavy EPROM proto cart - is out in full force in this setup, which went from some guy from The Software Toolworks, to someone else, to EBay, to some teenager for several hundred bucks a month or so ago. Hopefully there's more than one to go around out there (ie. to me)...