Examine source code of Language Manager

{
  "manifest_version": 2,
  "name": "Language Manager",
  "version": "1.1",
  "description": "Detect the language of selected text on a page.",
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Detect Language",
    "default_icon": {
      "128": "icon-128.png"
    }
  },
  "icons": {
    "128": "icon-128.png"
  },
  "applications": {
    "gecko": {
      "id": "{47775c29-cdde-4122-b2ad-bd9931bde6a5}",
      "strict_min_version": "109.0"
    }
  }
}