Useful in deployments where sockets are passed by systemd.
https:// {
bind socket-activation/https
respond "ok"
}
Using socket activation requires every site block to have explicit bind, it can be used in a snippet to avoid repetition.
systemd-socket-activate -l 443 --fdname=http3 /path/to/caddy run
FD to sockets mapping comes from go-systemd.