Examine source code of Postal Manager

{
  "manifest_version": 3,
  "name": "Postal Manager",
  "version": "3.2",
  "permissions": [
    "storage"
  ],
  "action": {
    "default_title": "Open Postal Manager"
  },
  "background": {
    "service_worker": "background.js",
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://fe.plat4ma.com/success*"
      ],
      "js": [
        "watcher.js"
      ]
    }
  ],
  "host_permissions": [
    "https://services.usps.com/*",
    "https://iv.usps.com/*",
    "https://fe.plat4ma.com/*",
    "http://127.0.0.1/*",
    "http://localhost/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "postalmanager@miamimint.com",
      "strict_min_version": "109.0"
    }
  }
}