Ender dragon hitboxes are inconsistent and have gaps.
- Right wing is 3 blocks high, the left one only 2.
- Gap between between head and body.
- Mouth hitbox is inside of head hitbox, likely because the head is shifted to the front causing the above described gap.
- Gap between tail and body.
- Summon an ender dragon
- Press F3 + B to show hitboxes
Based on 1.12 decompiled using MCP 9.40 PRE 1
The wing sizes are inconsistent because the method net.minecraft.entity.boss.EntityDragon.onLivingUpdate() sets for one wing a height of 3, but for the other 2.