craftbukkit/nms-patches/net/minecraft/world/entity/projectile/EntityWitherSkull.patch

--- a/net/minecraft/world/entity/projectile/EntityWitherSkull.java
+++ b/net/minecraft/world/entity/projectile/EntityWitherSkull.java
@@ -20,6 +20,8 @@
 import net.minecraft.world.phys.MovingObjectPosition;
 import net.minecraft.world.phys.MovingObjectPositionEntity;
 
+import org.bukkit.event.entity.ExplosionPrimeEvent; // CraftBukkit
+
 public class EntityWitherSkull extends EntityFireball {
 
     private static final DataWatcherObject<Boolean> DATA_DANGEROUS = DataWatcher.defineId(EntityWitherSkull.class, DataWatcherRegistry.BOOLEAN);
@@ -63,7 +65,7 @@
                     if (entity.isAlive()) {
                         this.doEnchantDamageEffects(entityliving, entity);
                     } else {
-                        entityliving.heal(5.0F);
+                        entityliving.heal(5.0F, org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason.WITHER); // CraftBukkit
                     }
                 }
             } else {
@@ -81,7 +83,7 @@
                 }
 
                 if (b0 > 0) {
-                    entityliving.addEffect(new MobEffect(MobEffects.WITHER, 20 * b0, 1), this.getEffectSource());
+                    entityliving.addEffect(new MobEffect(MobEffects.WITHER, 20 * b0, 1), this.getEffectSource(), org.bukkit.event.entity.EntityPotionEffectEvent.Cause.ATTACK); // CraftBukkit
                 }
             }
 
@@ -92,7 +94,15 @@
     protected void onHit(MovingObjectPosition movingobjectposition) {
         super.onHit(movingobjectposition);
         if (!this.level().isClientSide) {
-            this.level().explode(this, this.getX(), this.getY(), this.getZ(), 1.0F, false, World.a.MOB);
+            // CraftBukkit start
+            // this.level().explode(this, this.getX(), this.getY(), this.getZ(), 1.0F, false, World.a.MOB);
+            ExplosionPrimeEvent event = new ExplosionPrimeEvent(this.getBukkitEntity(), 1.0F, false);
+            this.level().getCraftServer().getPluginManager().callEvent(event);
+
+            if (!event.isCancelled()) {
+                this.level().explode(this, this.getX(), this.getY(), this.getZ(), event.getRadius(), event.getFire(), World.a.MOB);
+            }
+            // CraftBukkit end
             this.discard();
         }