Was looking at Firin Da Spell and see that it does not specify that the extra power granted lasts until the end of the turn. On the other hand, it doesn't say to add any resource tokens to the target unit either, like most other permanent benefit cards do. I always assumed it was until the end of the turn, hence why I didn't notice anything missing until now. Didn't see the card errata'd or addressed in the FAQ. Anyone know of any official ruling?

Nevermind: card reads "Target attacking unit" which, obviously, ends at end of the battlefield phase when all attacking units stop being attacking units.