Examine source code of Calculator Basic Fun

{
  "manifest_version": 2,
  "name": "Calculator Basic Fun",
  "version": "1.0",
  "description": "HTML calculator is used for performing basic mathematical operations like Addition, subtraction, multiplication, and division.",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/cacul-logo.png"
    }
  },
  "icons": {
    "128": "images/cacul-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c09c42c6-0767-4174-aefa-b82777d971b2}"
    }
  }
}