I disagree on the prototype idea, its probably just a limited production board made by a upstart

it could also hook up to the apple //c style monitors they used a combination of different signals on a 9 pin output including ntsc and more or less serial in the same plug, which included a what ? 10-12 inch "rgb" (which is total apple marketing crap in its glory days, if you look at a //c pinout) color monitor