[docs] Add link to browser extension repository

Author: jankeromnes

src/docs/browser-extension.md

@@ -25,4 +25,10 @@ A user can view an extension's options by right-clicking the extension icon in t
 
 ### Accessing the options on Firefox
 
-An Options page enables you to define preferences for your extension that your users can change. Users can access the options page for an extension from the browser's add-ons manager.
+An Options page enables you to define preferences for your extension that your users can change. Users can access the options page for an extension from the browser's add-ons manager.
+
+## Source Code
+
+Gitpod's browser extension is open source. You can check out its [source code](https://github.com/gitpod-io/browser-extension), or even open it in Gitpod:
+
+[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://github.com/gitpod-io/browser-extension)