I just found one I got years ago off ebay, still sealed in the plastic wrap that I don't need and wondered if anyone needed it for a DC devkit?
splith said it's for a Dreamcast Devkit, also known as Development Kit. A kit for programmers to develop games and software for the Dreamcast. This card is for the Devkit to be able to hook into a computer for programming, debugging, and much more. I would be interested if I had the rest of the kit and more programming understanding but I don't so pass.
I already knew that it was for a Katana Devkit, I wanted to know what the PCI Card was for, since Video Cards, Network Cards and Sound Cards go in PCI slots.