> (I don't know about YouTube, but I'd guess that's the case) YouTube delivers video in chunks over the standard HTTPS port 443, as does Twitch. YouTube suppor

> (I don't know about YouTube, but I'd guess that's the case) YouTube delivers video in chunks over the standard HTTPS port 443, as does Twitch. YouTube supports HTTP/3, so it will use UDP via QUIC if your browser and network also support it, but otherwise it will simply go over TCP.