editing/crashtests/forwarddelete-delete-after-justifyleft-indent.html

<script>
document.addEventListener("DOMContentLoaded", () => {
  const fieldset = document.querySelector("fieldset");
  document.documentElement.contentEditable = true;
  fieldset.contentEditable = false;
  document.execCommand("justifyLeft");
  document.designMode = "on";
  document.execCommand("indent");
  document.execCommand("forwardDelete");
  document.execCommand("delete");
});
</script>
<acronym readonly autofocus>
<sup>
<fieldset>

here is fieldset
</fieldset>
</acronym>
</html>