Which backend uses Firewalld to store the rules?

About

firewalld uses as backend:

• nftables (default)
• iptables (deprecated)

How to see the actual backend?

The configuration is firewalld system configuration.

grep -i backend /etc/firewalld/firewalld.conf

# FirewallBackend
# Selects the firewall backend implementation.
FirewallBackend=nftable