This is the default example configuration of dynamicmaps.cf provided by Postfix. This config file was generated by Postfix running on Debian 9.
It is located under: /etc/postfix/dynamicmaps.cf
sqlite postfix-sqlite.so dict_sqlite_open
Download the raw file with wget or curl
wget -O dynamicmaps.cf.example http://exampleconfig.com/static/raw/postfix/debian9/etc/postfix/dynamicmaps.cf
curl http://exampleconfig.com/static/raw/postfix/debian9/etc/postfix/dynamicmaps.cf > dynamicmaps.cf.example
Other config files you might find useful