This addon wraps blizzard api functions to add information about internal cooldowns to many proc based items. This allows it to display a cooldown for the item while maintaining good functionality with most UI mods.
This addon supports item based procs and set based procs as well as meta gems and enchants. Gems and enchants must be entered manually as detailed in the install guide.
Hidden Cooldown will not work with every proc based item in the game by default. Some do not follow the item description template that I use to determine which buffs to watch for. It is possible to add items manually. To do that edit hiddencooldown.lua within the wtf character folder.