Examine source code of NoPhone TOTP

{
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "nophone-totp@kybiu.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "name": "NoPhone TOTP",
  "version": "1.1",
  "description": "Time-based one time password (TOTP) generator with multi-entry storage.",
  "icons": {
    "48": "icons/icon48.ico",
    "96": "icons/icon96.ico",
    "128": "icons/icon128.ico"
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon48.ico",
      "96": "icons/icon96.ico",
      "128": "icons/icon128.ico"
    }
  },
  "permissions": [
    "storage",
    "clipboardWrite",
    "tabs",
    "activeTab"
  ],
  "host_permissions": [],
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'; style-src 'self' https://cdn.jsdelivr.net https://cdnjs.cloudflare.com;"
  }
}