What do I do with the ".ext?"

dovecot 2.3.15 opensuse LEAP 15.4

I am installing dovecot and have postfix as the SMTP agent. It also needs to use a MySQL database. In </etc/dovecot> there is the main dovecot.conf file, and a number of other files with the extension ".conf.ext." It is not clear how to use these. I could nothing in the documentation that discusses it. Do I copy one, say dovecot-sql.conf.ext, modify it:

• rename the copy without the ".ext?"
• or move the copy to the "conf.d" directory, with or without the "ext?"

-- James Moe moe dot james at sohnen-moe dot com 520.743.3936 Think.