Create JSDOC annotations for a imported third party class with no JSDOC available?

Question

I am using quickjs JS Engine, which provide means to export native classes (written in C++) to be imported in as ES module in the regular JS code.

import {NativeClass} from "libSomeAwesomeCode.so";

This Native class have properties and methods with params. How do I define the JSDOC for this class (this class is written in C) ?