https://gitlab.torproject.org/tpo/applications/tor-browser/-/blob/tor-browser-140.3.0esr-15.0-1/browser/app/profile/001-base-profile.js#L138 There is a problem with the spelling on line 138. "dom.security.https_first_add_exception_on_failiure" should be spelled "dom.security.https_first_add_exception_on_failure". On Firefox, it is spelled properly, but the misspelling carries exists in Tor Browser and Mullvad Browser.