Has anyone done the 360 degree interior tour of the RX-8 on Mazda's web site and pointed the camera all the way up? It looks like there's some kind of ABS-line slot in the moonroof cover. Does anyone know what it is, and how the moonroof works? Is it one of those where the interior roof panel slides back to expose the glass, and then the glass can also be opened?

Yes, it's like that on my Millenia. However if you open the sunroof with the switch it will pull that shade back with it. If you tilt the roof then you'll need to open it manually.

SO is the slot to let sunlight in when the shade is closed?

Our 2003 Protege 5 has the same sunroof arrangement. I'm 99% sure the slots are there so the sunroof can be tilted for ventilation purposes while the shade part of the sunroof is closed.