Don't need to load polyfills

.browserslistrc

@@ -2,5 +2,5 @@ chrome >= 70
 chromeandroid >= 70
 ios >= 12
 safari >= 12
-edge >= 17
+edge >= 18
 firefox >= 68

src/playground/editor.jsx

@@ -1,12 +1,6 @@
 // must be first for progress bar to work
 import "./tw-hacky-progress-bar";
 
-// Polyfills
-import 'es6-object-assign/auto';
-import 'core-js/fn/array/includes';
-import 'core-js/fn/promise/finally';
-import 'intl'; // For Safari 9
-
 import React from 'react';
 import ReactDOM from 'react-dom';