I have the Magento_Cron module disabled, so as far as I know, no cron jobs should be running in my environment.
Every minute or so, the text...
There are no commands defined in the "cron" namespace. Did you mean this? setup:cron
...gets appended to the file
var/log/magento.cron.log (without me doing anything).
The posts that I've found about this issue mostly say that it's due to a missing
/etc/module.xml file, but those posts seem to reference this error as a response to running some command line command. Since in my case the error gets logged without me doing anything, I'm at a loss of how to figure out what's causing it. Additionally, since the error is happening automatically in a log file, I don't know how to turn on any additional logging.