[jeroenhd]

HTTP/3 uses QUIC as a layer 4 equivalent (which is actually just UDP with extra implications in practice). Not many services leverage standards-compliant QUIC other than HTTP/3, but you don't need to do HTTP to get the same protocol working.

If anything, HTTP/3 running on top of QUIC forced shitty middlebox vendors to de-ossify by permitting any QUIC-based protocol, as they cannot practically distinguish a new HTTP/3 connection from a QUIC connection.

[afiori]

My understanding is that they cannot even really recognise a QUIC connection (maybe the first time, but not after ip roaming)