Bukkit/CraftBukkit — pull request #916 by aikar (2012-11-05 00:39:49+00:00)
Title: Do not filter DamageCause for EntityDamageEvent. Fixes BUKKIT-2781

Anything that damages an Entity should call EntityDamageEvent, so that plugins may have access to cancel it.

This makes it so plugins can access (and block) Anvil damage, and ensures plugins can block all damage events.

I would like to know why this line was in there in the first place though...