Examine source code of Clickjacking Checker

{
  "manifest_version": 2,
  "name": "Clickjacking Tester",
  "version": "1.0",
  "description": "Test websites for clickjacking vulnerabilities.",
  "permissions": [
    "tabs",
    "activeTab",
    "<all_urls>"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{095efc63-26a2-44ff-82c8-34a018328825}"
    }
  }
}