Examine source code of Contacts

{
  "manifest_version": 2,
  "name": "Contacts",
  "description": "The fancy Pixel Maniacs Contacts-Tool",
  "version": "1.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "{4aee9db2-518a-4ee1-9322-cc0a4f432432}",
      "strict_min_version": "60.0"
    }
  },
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": {
      "80": "icons/contacts.png"
    }
  },
  "icons": {
    "80": "icons/contacts.png"
  },
  "permissions": [
    "activeTab",
    "<all_urls>"
  ],
  "web_accessible_resources": [
    "iframe.html"
  ]
}