PC hardware question

[Daniel Browning]

I would check the case manufacturer's manual. It could be related to a water cooling system of some sort, more than the typical "two holes for tubes".

Another possibility: I've seen things like you describe for firewire, MIDI, serial ports, etc. They come with a cable that goes to the correct spot on the motherboard. It's possible that your case didn't come with them because so few people ever need them, and perhaps they are an optional accessory available for purchase.