It's a bi-directional led -- two led's in a common package in back to back configuration.
It looks like a single led with equal lead size.
I don't know why they used it for computer application even though DC power is readily available. Actually this led is not required for this application, they can go with traditional led's.
I came across these kind of leds in AC application. In power panel indicator lamps.
There will be no DC supply available so they will use a capacitive/resistive power supply and connect a bi-directional led to it. One led will be in forward bias for 1st half cycle other led will be forward biased for 2nd half cycle. So there is no need of bridge rectifier, filtering capacitor here.
So they can save some money in high volume production.
For capacitive and resistive power supply please see schematic. The component values we are going to select based on LED properties
simulate this circuit – Schematic created using CircuitLab