Examine source code of Page Speed Checker

{
  "manifest_version": 2,
  "name": "Page Speed Checker",
  "version": "1.0",
  "description": "Measure the loading speed and size of any webpage. Displays DOM load time, full load time, and page size with a deep blue dashboard interface.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{49bd166a-6817-42e8-b6c1-3a9e28b51e57}"
    }
  }
}