For Commit rules in Herald, the Commit Fields → Reviewer field evaluates to only the first reviewer for the associated revision. This is legacy behavior from an era (pre T1279) where revisions broadly had only one reviewer.
This doesn't match up with modern behavior very well, and modern users almost certainly want Related Fields → Accepting reviewers instead. The "Reviewer" field is probably never useful, and potentially confusing.
It's not entirely clear how to best move forward:
- Remove the field -- but we break existing rules.
- Migrate the field to "Accepting reviewers" -- but we change the behavior of existing rules.
- Rename the field to "Reviewer (Legacy)", or move it to a "Legacy" category -- maybe improves things, but really just punts this.