packages/react-devtools-shell/perf-regression.html

<!doctype html>
<html>
  <head>
    <meta charset="utf8">
    <title>React DevTools</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
      * {
        box-sizing: border-box;
      }
      body {
        margin: 0;
        padding: 0;
        font-family: -apple-system, BlinkMacSystemFont, Segoe UI, Helvetica, Arial,
          sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol;
        font-size: 12px;
        line-height: 1.5;
      }
      #iframe {
        position: absolute;
        top: 0;
        left: 0;
        width: 100vw;
        height: 60vh;
      }
      #devtools {
        position: absolute;
        bottom: 0;
        left: 0;
        width: 100vw;
        height: 40vh;
      }
      #load-devtools {
        margin: 20px;
      }
    </style>
  </head>
  <body>
    <iframe id="iframe"></iframe>
    <div id="devtools">
      <button id="load-devtools">Load DevTools</button>
    </div>
    <script src="dist/perf-regression-devtools.js"></script>
  </body>
</html>