Mobs drop their heads when killed by a player. Almost every mob that does not drop it's head / skull in the vanilla game now has a chance to drop their head when killed by the player.
Updated for 1.17.30
+ Updated vanilla entity files for Husk, Rabbit & Zombie Villager
New heads for 1.17
+ Glow Squid
+ Goat & Screaming Goat
+ Axolotl Variants
New loot system to make upgrading to future packs better
Drop rates have been tweaked for Bedrock Edition.