So here it is…
Or from code:
SiteSetting.disable_emails = "non-staff"
My setting when I got there was no disable, meaning enabled 
But my script doesn’t touch this setting; and in base.rb it is set to yes. So I currently have no explanation for how emails got enabled (or failed to get disabled) 
I even checked the code of the only plugin I’m using, discourse-migratepassword, but no mention of this option there, either.
No reply needed - my problem is solved, thanks for that, I am left wondering what happened but that is a minor concern at this point.