chromium/third_party/blink/web_tests/external/wpt/css/css-anchor-position/anchor-center-scroll-ref.html

<!DOCTYPE html>
<title>CSS Test Reference</title>
<body style="margin:0">
  <div id="scroller" style="width:400px;height:400px;overflow:auto;background:orange">
    <div style="height:100px"></div>
    <div style="width:100px;height:100px;background:pink">
      <div style="height:25px"></div>
      <div style="width:50px;height:50px;background:purple"></div>
    </div>
    <div style="height:1000px"></div>
  </div>
</body>
<script>
  scroller.scrollTop = 100;
</script>