This addon is really handy if you would like to know which pet abilities your opponent is using, and what the cooldown is from each ability, it will also show the cooldown of each ability when it is on cooldown.
The icons are set into the pet battle UI frame, you will see them in the top bar next to each pet.
Hovering over each ability will show you information about the ability as well.
Special thanks to Derangement, the original author of the addon -> the addon was called DerangementPetBattleCooldowns before, and I hope I will do him proud to keep his addon going!