How to set up Logwatch configuration overrides?

I've been running Logwatch on a Raspberry Pi for some time and learned a lot from it. I decided to install on a Mac (Intel iMac running Sequoia) via MacPorts. The Logwatch configuration file

/opt/local/share/logwatch/default.conf/logwatch.conf

says to override default variables by putting them in the following file:

/etc/logwatch/conf/logwatch.conf

However, that directory does not exist. So, I'm lost. Do I need to create that directory or does the override file go somewhere else?