Fireworks entities spawned with the "Silent" tag only partially respect that flag. The server-side travel sounds are muted, but the client-side explosion sound is not.

Example:

/summon fireworks_rocket ~ ~1 ~ {Silent:true,LifeTime:30,FireworksItem:{id:fireworks,Count:1,tag:{Fireworks:{Flight:2,Explosions:[{Type:1,Flicker:0,Trail:0,Colors:[I;2651799],FadeColors:[I;2437522]}]}}}}

It would be really great for map makers and modders if we could use the firework explosion effects without the boom noise!

Thank you for your consideration.