This is the default example configuration of postfix.conf provided by Postfix. This config file was generated by Postfix running on Ubuntu 18.04.
It is located under: /etc/rsyslog.d/postfix.conf
# Create an additional socket in postfix's chroot in order not to break
# mail logging when rsyslog is restarted. If the directory is missing,
# rsyslog will silently skip creating the socket.
$AddUnixListenSocket /var/spool/postfix/dev/log
Download the raw file with wget or curl
wget -O postfix.conf.example http://exampleconfig.com/static/raw/postfix/ubuntu18.04/etc/rsyslog.d/postfix.conf
curl http://exampleconfig.com/static/raw/postfix/ubuntu18.04/etc/rsyslog.d/postfix.conf > postfix.conf.example
Other config files you might find useful