Examine source code of Click

{
  "manifest_version": 2,
  "name": "Click",
  "version": "1.1resigned1",
  "description": "Plays a click sound when you click on a link.",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "background": {
    "scripts": [
      "click.js"
    ]
  },
  "permissions": [
    "webNavigation"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d5752d63-afb5-4bfb-9368-4b3063c29b8a}"
    }
  }
}