Examine source code of Nutzernamen Generator

{
  "manifest_version": 2,
  "name": "Simple Username Generator",
  "version": "1.0",
  "description": "Generate usernames based on input fields",
  "icons": {
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "icon.png",
      "128": "icon.png"
    },
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{17e52295-3f75-4f45-9ba9-6c63af634c87}"
    }
  }
}