Examine source code of Auto Refresh

{
  "manifest_version": 2,
  "name": "Auto Refresh",
  "version": "1.0",
  "description": "An addon to refresh the browser automatically",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Auto Refresh",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{458c7908-b50e-47f4-92ff-4599fa76995a}"
    }
  }
}