If I search for what a session cookie is the common answer will be something like "It's a temporary cookie that's erased from your device once you close your web browser". If I: 1. Open Firefox. 2. Navigate to website A. 3. Login 4. Close the browser(All windows) without loging out from the website. 5. Open Firefox. 6. Navigate to website A. If the website has marked it's session cookie as a "session cookie" I will be logged out when I visit website A again. I can't retrieve my previous session, although It's alive on the server. The browser has seemingly, as it should, deleted my cookie since it was a session cookie. However(!), If i repeat the steps above, but after step 5 hit ctrl+shift+t, the browser remembers my session cookie and I'm back in. Although Firefox was supposed to forget my session cookie.