Examine source code of Detect Language

{
  "name": "Detect Language",
  "description": "Detects up to 3 languages and their percentages of the provided string",
  "version": "1.9",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{a6daa9b5-88b5-421e-851b-bdca7982d277}"
    }
  }
}