A way of getting the browser to behave and support the latest specifications.
You can install polyfills using component:
component install remy/polyfills
If you'd like to include all polyfills (except device motion), you can just:
require( 'polyfills' );
If you'd only like a specific polyfill, you can require indivual ones like this:
require( 'polyfills/classList' ); // now we can use classList in lots of browsers! element.classList.add( 'foo' );