plugins/_office/webui/main.html

<html class="office-modal">
<head>
  <title>Documents</title>
  <script type="module">
    import { store } from "/plugins/_office/webui/office-store.js";
  </script>
</head>
<body class="office-modal-body">
  <x-component path="/plugins/_office/webui/office-panel.html" mode="modal"></x-component>
</body>
</html>