The mobo mounts to a tray with port connections. The tray slides into a metal box that is attached to the modified bottom of the Mac SE. I am not sure what any of these modifications are for, but they are not present on any other SE board I have. The only one I suspect is factory is the RAM configuration mini-board. I have seen it before, but I am not sure if the criss-cross of resistors is part of this mod.