I guess technically a CPU core within the GPU ASIC block loads code into the main CPU. What a weird design. Feels like the kinda of things that Wozniak would come up with to shave cost from the Apple Macintosh.
Woz also designed Apple Desktop Bus for keyboards and mice. First used on the Apple IIGS, and then on Macs from Macintosh II onwards up until it was replaced by USB.
Ehhh, video core is basically just a (iirc multi-core/-thread) vector processor.
Funnily enough, this also makes these rather cheap number crunching hard real time chips with the high-bandwidth IO (for hard-real-time) of a Pi. Notably, it's camera/display interfaces.