Examine source code of Merge All Windows

{
  "name": "Merge Windows",
  "version": "1.1resigned1",
  "homepage_url": "https://singleclickapps.com/merge-windows",
  "description": "Merge all browser windows in one",
  "icons": {
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "background": {
    "persistent": false,
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon24.png",
    "default_title": "Merge All Windows"
  },
  "permissions": [
    "tabs",
    "contextMenus"
  ],
  "offline_enabled": true,
  "options_ui": {
    "page": "options.html"
  },
  "incognito": "spanning",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{07532c74-a5e9-491b-82d6-e55bc0e03d67}"
    }
  }
}