&gt; I&#x27;d expect I&#x27;m not the only one who wants to pin few certs for sites that I visit frequently.<p>How can you tell what the backup pin for those websites would be without the owner publishing the HKPK headers? How do you know the max-age of their current pin?<p>It sound a bit like trying to stuff things into the browser&#x27;s cache - a road to disaster.