Most ATX motherboards have those same pins for 'interfacing' with the computer case... depending on the manufacturer they vary on position (hence loose wires at the case end) but never function. So i guess there is a standard somewhere.
they usually looks like this:
and you connect wires like these:
I looked on the ATX standard but there only seems to be board sizing and the power connector.
I'd love to have the specs for everything on that bundle... but if not, to unblock my work i'd just need to know now the LED (power_led, or p_led) specs. Do I need a resistor? or just a led? which leds are compatible? 5V? 3V?