Examine source code of Geometry Shape

{
  "manifest_version": 2,
  "name": "Geometry Shape Calculator",
  "version": "1.0",
  "description": "Calculate the area and perimeter of basic geometric shapes.",
  "icons": {
    "48": "icons/geometry-calculator-icon-48.png"
  },
  "permissions": [],
  "browser_action": {
    "default_icon": "icons/geometry-calculator-icon-48.png",
    "default_popup": "popup.html",
    "default_title": "Geometry Calculator"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{06cbb220-ff58-42b5-ba50-7ea2bc98e18d}"
    }
  }
}