Examine source code of Baby XSS

{
  "manifest_version": 2,
  "name": "Baby XSS",
  "description": "XSS made easy by Xanco",
  "version": "1.0",
  "default_locale": "en",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "menus",
    "activeTab",
    "clipboardRead",
    "clipboardWrite"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{fb2669e3-e4c5-4f57-9e4f-157653be0c33}"
    }
  }
}