This is what appears in my game output.

[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:block.brewing_stand.brew
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:block.chorus_flower.death
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:block.chorus_flower.grow
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:enchant.thorns.hit
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.guardian.thorns
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.horse.eat
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.player.attack.crit
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.player.attack.knockback
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.player.attack.parry
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.player.attack.strong
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.player.attack.sweep
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.player.attack.weak
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.rabbit.attack
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.shield.block
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.shulker.ambient
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.shulker.close
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.shulker.death
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.shulker.open
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.shulker_bullet.hit
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.shulker_bullet.hurt
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.witch.ambient
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.witch.death
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.witch.drink
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.witch.hurt
[10:34:13] [Client thread/WARN]: Missing sound for event: minecraft:entity.witch.throw

Please don't remove this msg from the launcher, instead add these sounds to the game.