What parents get, and stopping them
The email comes from your group, “via Badges”. It says how many badges they've earned, the ones earned this term (or waiting to be presented), and the badges they're working towards, with how far they are and the next meeting or event that covers them. The full report is attached as a PDF, the same one you'd print.
Every email has a link to stop them. It stops badge report emails from your group to that address straight away, without signing in, and the address shows as “asked to stop” next time you send. Mail apps' own Unsubscribe button does the same.
Addresses are read from OSM each time you send and never kept, so to change who gets them, change the contact in OSM.