diff --git a/aio/src/main.ts b/aio/src/main.ts
index a59cc3382d..a9ca1caf8c 100644
--- a/aio/src/main.ts
+++ b/aio/src/main.ts
@@ -1,10 +1,8 @@
-import 'core-js/es7/reflect';
-import 'zone.js/dist/zone';
-
-import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
 import { enableProdMode } from '@angular/core';
-import { environment } from './environments/environment';
+import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
+
 import { AppModule } from './app/app.module';
+import { environment } from './environments/environment';
 
 if (environment.production) {
   enableProdMode();
diff --git a/aio/src/polyfills.ts b/aio/src/polyfills.ts
index 4a9f6bbcfd..53bdaf1b86 100644
--- a/aio/src/polyfills.ts
+++ b/aio/src/polyfills.ts
@@ -1,7 +1,24 @@
+/**
+ * This file includes polyfills needed by Angular and is loaded before the app.
+ * You can add your own extra polyfills to this file.
+ *
+ * This file is divided into 2 sections:
+ *   1. Browser polyfills. These are applied before loading ZoneJS and are sorted by browsers.
+ *   2. Application imports. Files imported after ZoneJS that should be loaded before your main
+ *      file.
+ *
+ * The current setup is for so-called "evergreen" browsers; the last versions of browsers that
+ * automatically update themselves. This includes Safari >= 10, Chrome >= 55 (including Opera),
+ * Edge >= 13 on the desktop, and iOS 10 and Chrome on mobile.
+ *
+ * Learn more in https://angular.io/docs/ts/latest/guide/browser-support.html
+ */
 
+/***************************************************************************************************
+ * BROWSER POLYFILLS
+ */
 
-// This file includes polyfills needed by Angular and is loaded before the app.
-// You can add your own extra polyfills to this file.
+/** IE9, IE10 and IE11 requires all of the following polyfills. **/
 // import 'core-js/es6/symbol';
 // import 'core-js/es6/object';
 // import 'core-js/es6/function';
@@ -15,24 +32,37 @@
 // import 'core-js/es6/regexp';
 // import 'core-js/es6/map';
 // import 'core-js/es6/set';
-import 'reflect-metadata';
+
+/** IE10 and IE11 requires the following for NgClass support on SVG elements */
+// import 'classlist.js';  // Run `npm install --save classlist.js`.
+
+/** IE10 and IE11 requires the following to support `@angular/animation`. */
+// import 'web-animations-js';  // Run `npm install --save web-animations-js`.
 
 
-// If you need to support the browsers/features below, uncomment the import
-// and run `npm install import-name-here';
-// Learn more in https://angular.io/docs/ts/latest/guide/browser-support.html
+/** Evergreen browsers require these. **/
+import 'core-js/es6/reflect';
+import 'core-js/es7/reflect';
 
-// Needed for: IE9
-// import 'classlist.js';
 
-// Animations
-// Needed for: All but Chrome and Firefox, Not supported in IE9
-// import 'web-animations-js';
+/** ALL Firefox browsers require the following to support `@angular/animation`. **/
+// import 'web-animations-js';  // Run `npm install --save web-animations-js`.
 
-// Date, currency, decimal and percent pipes
-// Needed for: All but Chrome, Firefox, Edge, IE11 and Safari 10
-// import 'intl';
 
-// NgClass on SVG elements
-// Needed for: IE10, IE11
-// import 'classlist.js';
+
+/***************************************************************************************************
+ * Zone JS is required by Angular itself.
+ */
+import 'zone.js/dist/zone';  // Included with Angular CLI.
+
+
+
+/***************************************************************************************************
+ * APPLICATION IMPORTS
+ */
+
+/**
+ * Date, currency, decimal and percent pipes.
+ * Needed for: All but Chrome, Firefox, Edge, IE11 and Safari 10
+ */
+// import 'intl';  // Run `npm install --save intl`.
diff --git a/aio/src/test.ts b/aio/src/test.ts
index 7eef72157c..9bf72267e9 100644
--- a/aio/src/test.ts
+++ b/aio/src/test.ts
@@ -1,6 +1,5 @@
 // This file is required by karma.conf.js and loads recursively all the .spec and framework files
 
-import 'zone.js/dist/zone';
 import 'zone.js/dist/long-stack-trace-zone';
 import 'zone.js/dist/proxy.js';
 import 'zone.js/dist/sync-test';