The "implementation-dependent String" returned from Function.prototype.toString() is now a fully-specified String, which is a substring of the source code that defines the function. For example, this preserves whitespace and comments between the "function" keyword and the function name identifier. For functions created with CreateDynamicFunction (such as through `new Function()`), the String is fully-specified and includes the parameters passed to CreateDynamicFunction.
Docs: https://github.com/tc39/Function-prototype-toString-revision https://tc39.github.io/Function-prototype-toString-revision/