See https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/40398#note_2733987 Specifically: > [1699490](https://bugzilla.mozilla.org/show_bug.cgi?id=%201699490) - We need to ensure that `network.http.http3.enabled` stays 'false' as tor does not support UDP and therefore QUIC and therefore HTTP/3.