Examine source code of DualSearch

{
  "manifest_version": 2,
  "name": "DualSearch",
  "version": "1.0",
  "description": "Переключение между Google и Yandex поисковыми системами",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon-inactive.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "applications": {
    "gecko": {
      "id": "DualSearch@verstov"
    }
  }
}