Examine source code of Page Speed Tester

{
  "manifest_version": 2,
  "name": "Page Speed Tester",
  "version": "1.0",
  "description": "Test the loading speed of the current page.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0e6a3d3d-f8f6-40d5-b925-3041aef58960}"
    }
  }
}