How does Potion of Unbridled Fury work?

Hi, I have a question about this pot (And any pot similar to this one, bursting blood and such)

How does potion of unbridled fury work? Does the damage proc depend of the amount of abilities I cast or is it automatic… meaning that it can proc from white damage and giving haste a better value?

Tyvm

Late reply…but in some way it does have more value for people who can attack “fast”, but considering it has a 20 RPPM, I can’t imagine there’s any class in the game that can’t perform at least 20 damaging attacks in a full minute. It basically has a chance to add a flat amount of damage to each of your attacks scaling with vers/crit and procs about 20 times a minute.