why don't string classes have symbol.toStringTag?

new String('')[Symbol.toStringTag] is undefined

I'm just wondering why it missing that?

Because Object.prototype.toString has a hardcoded early return path for anything that predates ES6, for web compat - so there’s no need for it.
https://tc39.es/ecma262/#sec-object.prototype.tostring

Hmm, ok thanks for the explanation.
Kind of wished that all those things had symbol.toStringTag also...

Could you expand on why you’d find it useful to have ToStringTag on the prototype of String,Number,Boolean etc thanks!