You're right, I wasn't quite sure what to make of it, but that's the rug pattern showing through the access slot for the AB Cable Connection.

That is one slick cooling system, I wonder if thy notched out the chassis to make the rectangular hole the fan covers a full square. I'd LOVE to see a shot of that bracket holding the fan and the paper air dam. I'm wondering if it bends down over the right edge of the chassis to block the right side vents somewhat. That'd have the fan accelerating an increased airflow across the MoBo and Radius Card from the left side vents, that's the way I'd do it for cooling something pretty warm . . .

. . . I'm thinking that there may have been a Mac Plus version of the Radius 16 in there. :?:

edit:

:lol: Second hit! I just googled: "radius 16" accelerator "mac plus"

Googling this kinda stuff only to find myself is beginning to make me feel like the Worm Ouroboros munching on eight year old tail! 8-o