Wowhead believes it has found Dragonwrath's proc while mining away at the data in today's patch 4.2 PTR build. They discovered the spell Wrath of Tarecgosa (applied to the caster by a passive aura), which provides a chance to duplicate the damage caused by an offensive damaging spell. The effect of this damage would also be called Wrath of Tarecgosa, and the damage would be dealt as arcane damage. Double Pyroblasts, anyone?
It should be noted that this information is on the PTR and is in no way final. This could be just one effect Blizzard is experimenting with, or it may ultimately be used for something completely different. It is, however, the best lead we've seen so far.
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