Examine source code of Auto Refresh V2

{
  "manifest_version": 2,
  "name": "Auto Refresh",
  "version": "1.0",
  "description": "Automatically refresh the current page at a specified interval.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/refresh-48.png",
    "default_popup": "popup.html",
    "default_title": "Auto Refresh"
  },
  "icons": {
    "48": "icons/refresh-48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e12e8bef-6da3-44f2-b0a5-6909d1b8acd2}"
    }
  }
}