Fireworks do not cause knockback to either the player or mobs.

The bug

Firework do not cause knockback to mobs and players.

How to reproduce

1. Find or spawn a mob.
2. Detonate a firework near enough to cause damage.

   /give @p firework_rocket{Fireworks:{Flight:1,Explosions:[{Type:1,Flicker:1,Trail:0,Colors:[I;8073150],FadeColors:[I;8073150]}]}}
   

   → The mob / player takes no knockback.