react/packages/react-devtools-extensions/popups/restricted.html

<script src="shared.js"></script>
<link rel="stylesheet" href="shared.css" />
<style>
  html, body {
    min-width: 286px;
    min-height: 33px;
  }

</style>
<p>
  <b>This is a restricted browser page.</b>
  <br />
  React devtools cannot access this page.
</p>