I received an e-mail in my inbox with the subject line "MediaWiki message delivery left you a message on Wikipedia".
I know what this means (sort of), but this is pretty cryptic and unfriendly, I think. I suppose it could be worse (e.g., "MediaWiki message delivery left you a message on Wikimedia"), but still... perhaps we need to rethink how we structure subject lines like this. I imagine bots and other automated processes have a similar issue.
Copying a few people who might be interested in this ticket, not necessarily anyone related to e-mail subject lines in particular. I'm assuming HTML e-mails like these are from MediaWiki core, but I suppose it's possible they're not... hmmm.
See Also:
T71954: Add support to MassMessage to allow using the sender's username for deliveries