Thanks- I had not seen that document.
You would think I would have learned- my second programming job was writing and supporting an embedded processor using the Intel 8080. For 17 years. Even then finding the data from Intel was a challenge. (Before the Internet, of course).
I've copied the PDF. thanks again.
Note also that you have control over how the LEDs are used. Go into BIOS Setup and select Advanced and then Power. In the Secondary Power Settings, you can select the function, color and display mode (solid, flashing or pulsing) for each of the LEDs.