[RobertWHurst]

At least in V8 they are last I checked. The symbols feature is a property privacy feature. A symbol can be treated as a private secret owned by a library thus restricting access to a property on a shared object.

[qubyte]

This is untrue. Symbols provide no privacy. They provide a mechanism to avoid collisions. You can even ask an object for its symbol properties: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...