ES6 Transpiling and Polyfills: Mix vs. Laravel-Mix-Polyfill

Can anyone tell me exactly what does Laravel Mix provide in terms of js transpiling and polyfills? What does the laravel-mix-polyfill extension provide that Mix does not? I write js in ES6 and need it transpiled for older browsers. I know that Mix includes Babel and Core-JS. But I've haven't been able to find a clear explanation for what Mix provides in terms of transpiling and polyfill capabilities out of the box. And what does the laravel-mix-extension provide above and beyond what you get in Mix -- is it mainly customization options?