A user received an email due to a commit being pushed upstream and was confused why they got an email. They were not involved in an associated code review. After inspecting with `/mail` it was due to a Herald rule they configured a year or so back and had forgotten about. The Herald rule observes commits in a repository with an action to email (not subscribe).
Currently the contents of the email don't indicate why they received the email if it's the result of a Herald rule sending an email. Other similar actions do have an indication ("Herald added an auditor: Cat Watch"), though they do not specify which rule. Having something similar for email actions would avoid confusion (ex "Herald rule H20 emailed: you").
==== Steps to Reproduce
1. Create Personal Herald Rule on Commits
1. When all of "Diff content" contains "some obscure word only said every 4 blue moons"
2. Send me an email
2. Create commit with obscure word and push to repository
3. Review email received, note that the rule maker is listed as CC
coder committed rAd6d3ad6f80d90d: Task #1 - Nothing to see here.
Task #1 - Nothing to see here.
Test Plan: Nobody tests anymore
Reviewed By: reviewer
Differential Revision: https://phabricator.company.com/D1