Examine source code of World Capitals Trainer

{
  "manifest_version": 2,
  "name": "World Capitals Trainer",
  "version": "1.0",
  "description": "An interactive educational quiz to help users memorize capital cities of countries around the world.",
  "icons": {
    "48": "map_icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "World Capitals Trainer"
  },
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "{33972eae-291c-4ece-a8a2-49694d7dde1b}",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}