//id gives a useless ID

[dadodasyra]

//id should give a type name (minecraft:x), it can be obtained by GlobalItemDataHandlers::getSerializer()->serializeType($inhand)->getName()

[TheLemzz]

id returns a TypeId that can be used for //replace and other commands. Recently, I was unable to use the name of an item that is registered by a third-party plugin, and I used its typeId.