The bug

The string "death.attack.fireworks.item" shows its raw translation string instead of a translation.

How to reproduce

1. Craft a firework star with a red dye (or any dye), a piece of glowstone dust (optional) and a piece of gunpowder
2. Use the firework star with a piece of gunpowder and a piece of paper to craft fireworks
3. Rename a crossbow in an anvil (important)
4. Go to a very enclosed area (only two blocks high if possible)
5. Use the crossbow to shoot fireworks to the ceiling above you
6. Die from the explosions

The translation string's variables are shown on the image below (a resource pack to fix the death message was used).