Fireballs now give their entity to the damage handler

src/main/java/net/minecraft/server/EntityFireball.java

@@ -154,7 +154,8 @@ public class EntityFireball extends Entity {
             ExplosionPrimedEvent event = new ExplosionPrimedEvent(eventType, CraftEntity.getEntity(server, this), 1.0F, false);
             server.getPluginManager().callEvent(event);
             if (!event.isCancelled()) {
-                this.world.a((Entity) null, this.locX, this.locY, this.locZ, event.getRadius(), event.getFire());
+                // give 'this' instead of (Entity) null so we know what causes the damage
+                this.world.a(this, this.locX, this.locY, this.locZ, event.getRadius(), event.getFire());
                 this.C();
             }
             // CraftBukkit end