No CA and client certificates, but TLS works

[Joci78]

Dear community,

I don't know the encryption process in depth, but why does the setting given in the subject work?

MQTT Explorer v0.4.0-beta1 Mosquitto v2.0.17

My mosquitto.conf:

listener 8883 protocol mqtt certfile /etc/mosquitto/certs/server.crt keyfile /etc/mosquitto/certs/server.key require_certificate false tls_version tlsv1.2 cafile /etc/mosquitto/ca_certificates/ca.crt persistence true persistence_location /var/lib/mosquitto log_dest file /var/log/mosquitto/mosquitto.log log_type error log_type warning log_type notice log_type information connection_message true log_timestamp true log_timestamp_format %Y-%m-%dT%H:%M:%S allow_anonymous false password_file /etc/mosquitto/passwd include_dir /etc/mosquitto/conf.d