When we generate links from URL's in messages, we add rel="nofollow" to combat link spam. This change turns that into rel="nofollow noopener". This prevents the page at the end of the link from having access to the roundup window that displays the link. Details on the issue are are at: https://mathiasbynens.github.io/rel-noopener/ search web for noopener vulnerability. This problem usually requires a target="_blank" to really exploit it and we don't provide that. But adding noopener is extra protection.

<!-- dollarId: issue.item,v 1.4 2001/08/03 01:19:43 richard Exp dollar-->
<tal:block metal:use-macro="templates/page/macros/icing">
  <title metal:fill-slot="head_title">
  Item Not Found
  </title>
  <tal:block metal:fill-slot="body_title">
  Item Not Found
  </tal:block>

<td class="content" metal:fill-slot="content">
    There is no <span tal:content="context/_classname" /> with id
    <span tal:content="context/id"/>
</td>
</tal:block>