Yeah, that's the D-5.3.1 driver, the "universal" driver that will run just about anything. I presume the D means "Developer Version" - anyone know for sure?
AFAIK what makes it universal is simply the fact that the driver contains the appropriate text strings that tell it that any drive is supported. In other words, I don't think the driver has any actual additional code in it that specifically enables it to work with drives unsupported by the standard Apple driver of that era.
M