Website updates

Author: ahocevar

dist/doc/tutorials/background.html

@@ -75,7 +75,7 @@ <h2 id="overview">Overview</h2>
 <h2 id="public-api">Public API</h2>
 <p>OpenLayers is available as <a href="https://npmjs.com/package/ol"><code>ol</code> npm package</a>, which provides all modules of the officially supported <a href="../../apidoc">API</a>.</p>
 <h2 id="browser-support">Browser Support</h2>
-<p>OpenLayers runs on all modern browsers (with greater than 1% global usage).  This includes Chrome, Firefox, Safari and Edge. For older browsers, <a href="https://polyfill.io/">polyfills</a> will likely need to be added.</p>
+<p>OpenLayers runs on all modern browsers (with greater than 1% global usage).  This includes Chrome, Firefox, Safari and Edge. For older browsers, polyfills (<a href="https://polyfill-fastly.io">Fastly</a> or <a href="https://cdnjs.cloudflare.com/polyfill">Cloudflare</a>) will likely need to be added.</p>
 <p>The library is intended for use on both desktop/laptop and mobile devices, and supports pointer and touch interactions.</p>
 <h2 id="module-and-naming-conventions">Module and Naming Conventions</h2>
 <p>OpenLayers modules with CamelCase names provide classes as default exports, and may contain additional constants or functions as named exports:</p>

dist/en/main/ol/README.md

@@ -96,7 +96,7 @@ The [ol package](https://npmjs.com/package/ol) includes auto-generated TypeScrip
 
 ## Supported Browsers
 
-OpenLayers runs on all modern browsers (with greater than 1% global usage).  This includes Chrome, Firefox, Safari and Edge. For older browsers, [polyfills](https://polyfill.io/) will likely need to be added.
+OpenLayers runs on all modern browsers (with greater than 1% global usage).  This includes Chrome, Firefox, Safari and Edge. For older browsers, polyfills ([Fastly](https://polyfill-fastly.io) or [Cloudflare](https://cdnjs.cloudflare.com/polyfill)) will likely need to be added.
 
 ## Documentation