What about CDATA; which XML and XHTML support? HTML5 does not support CDATA.

CDATA: https://en.wikipedia.org/wiki/CDATA

  <![CDATA[
  ]]>

  <script>
  <![CDATA[
  x = {"<!--":""};
  ]]>

  <![CDATA[
  {{json.dumps(["<!--"])}}
  ]]>
  </script>