Examine source code of Generate random passwords

{
  "name": "Advanced Random Password Generator",
  "version": "3.0",
  "description": "Generates a random password or passphrase",
  "manifest_version": 2,
  "icon": [
    {
      "src": "icon16.png",
      "sizes": "16x16",
      "type": "image/png"
    },
    {
      "src": "icon48.png",
      "sizes": "48x48",
      "type": "image/png"
    },
    {
      "src": "icon128.png",
      "sizes": "128x128",
      "type": "image/png"
    }
  ],
  "action": {
    "default_icon": "icon16.png",
    "default_popup": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8523ea76-c67f-4a3f-8188-d5cc91ec9e6a}"
    }
  }
}