Examine source code of Quick Square Calculator

{
  "manifest_version": 2,
  "name": "Quick Square Calculator",
  "version": "1.0",
  "description": "Enter a number and get its square instantly.",
  "permissions": [],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6307e620-6968-48ef-8471-08d08686970e}"
    }
  }
}