I've noticed that searches retain information about my previous searches after I close the browser; 'Delete cookies and site data when Firefox is closed' setting is selected. My tests seem to point to a security loophole with Cached Web Content. Question: how can I ensure privacy settings are honored, or, if there is a loophole, how can I get Firefox to also clear Cached Web Content on close? In my repeated test cases, I used bing to search for '5/8 irrigation kit', then closed the browser and reopened. Cookies and site data show 0 bytes (see attached images), Cached Web Content show something greater than 0. Next, I go to bing.com/news, scroll through stories, and see an advert for an irrigation kit as one of the sponsored adverts. As a further test after the original search, I try the following to see if I was being track another way, with the same resulting sponsored advert showing: * Restarted laptop * Restarted ONT (to get a new IP) and wifi The following 2 scenarios seemed to resolve the issue after the original search and seeing the same resulting sponsored advert: * Turned on VPN * Cleared Cached Web Content Clearing Cached Web Content seems to be the solution, and a possible privacy loophole. Cached Web Content is not part of the auto-delete-at-close feature. Oddly, I haven't been able to consistently replicate the above starting with the VPN on and having it on through the tests. It sometimes shows the same resulting sponsored advert, and sometimes not. I tried to replicate this with Safari. It's auto-delete feature at close and similar privacy setting seems to work according to what I would expect with the same test scenario; which is, no previous search-informed sponsored advert. Details: * Firefox 76.0.1 (64-bit) * Firefox privacy settings shown in attached images * MacBook Air 2019 * macOS Catalina Version 10.15.4 * Verizon Fios