Guild Wars 2

Wiki says it can only drop from Siax the Corrupted. However today I got one from MAMA, so apparently every boss can probably randomly drop it.
For those who don’t know it appears as a 3rd reward after defeating a boss.
As normally you get 2, where one is guild decoration/s and the other is personal reward like power cores.

I’ve personally gotten one from MAMA, one guildie that got it from Siax, and one that got it from the end boss, if I remember correctly.