As part of T331444: MediaWiki:GrowthMentors.json: Add a write-only username field, Growth-Team added a write-only username field to MediaWiki:GrowthMentors.json, which contains a list of available mentors. This is useful for administrators with a need to make a manual edit to the field, as they no longer need to find out the user ID manually (ie. via the API or public database replicas).

However, the newly-added username field doesn't handle renamed users well (if a mentor gets renamed, their username is only updated whenever someone makes a change to the structured mentor list in some Growth-curated way [change a weight/message via the Mentor dashboard, (un)enroll, etc.]).

It would be great to handle renames more nicely. However, for orientation purposes, the T331444-implemented version should be sufficient.