nginx 1.22 and the HTTP/3 that is still experimental

1.22 is the stable branch for 2022 and QUIC support is in a separate experimental branch, which is not the same as a feature flag.

$ nginx -V 2>&1 | tr ' ' 'n' | grep -c http_v3
0

# HTTP/3 in 2022 means either:
#   the nginx-quic branch, built from source, unsupported
#   a CDN in front that terminates it
#   Caddy or a different server entirely

# HTTP/2 is stable and is where the wins already are:
listen 443 ssl;
http2 on;   # 1.25 syntax; in 1.22 it is `listen ... http2`

The distinction matters because HTTP/3 was widely discussed in 2022 and widely not deployed, and building nginx from an experimental branch for a marginal latency improvement on a small number of connections is rarely the best use of an afternoon. A CDN terminating it is the version that is actually available.