iptables debugging no longer working with Debian 10 (and iptables-legacy; after upgrading from Debian 9) [closed]
Now it looks as if this kind of iptables debugging does in fact still work under Debian 10 as it did previously for me under Debian 9.
Apparently I had made a mistake by installing rules for iptables debugging before recreating targeted Kubernetes services, etc. That way the iptable rules and Kubernetes resources were out of sync with respect to cluster IPs, node ports, pod IPs, etc., and so the rules never fired with traffic to those services, etc.