Explain when mailingID and messageTemplateID are passed through
Created by: bhahumanists
Linked to https://github.com/civicrm/civicrm-core/pull/15306
Created by: bhahumanists
Linked to https://github.com/civicrm/civicrm-core/pull/15306
This should have waited for a core release but it's probably not important enough to revert.