Was able to find it.  Actually it&#x27;s using etags.  They work even if you disable cookies.  Perfect identification, similar to cookies.  Sites were using it before it came to light:<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;HTTP_ETag#Tracking_using_ETags" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;HTTP_ETag#Tracking_using_ETags</a>