It seems this is not widely known, but in the “Highest security settings” box, a note should be added stating that the Tor Browser must be restarted after changing the security level, or else you’ll have a different fingerprint than other users who started the browser at a specific level, as not all preferences can be applied without a restart—resulting in a false sense of security that the selected level is fully attained. This note should also be added to the Tor Browser and Mullvad Browser section on Privacy Guides.