Examine source code of Smart Page Refresher

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.5",
  "description": "__MSG_extensionDescription__",
  "permissions": [
    "activeTab",
    "tabs",
    "notifications",
    "storage",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png",
      "128": "icons/icon-128.png",
      "256": "icons/icon-256.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "128": "icons/icon-128.png",
    "256": "icons/icon-256.png"
  },
  "web_accessible_resources": [
    "alert.mp3"
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "119.0",
      "id": "{cf319a01-310e-1e6b-1a30-33052c478505}"
    }
  }
}