The use case described makes sense to me, thanks for filling the ticket @Xaosflux .

I'm wondering, would it make more sense to add a write-only username field to GrowthMentors.json instead (the username won't be ever read from GrowthMentors.json, the ID would still be the way how GrowthExperiments identifies enrolled mentors, but it would be there to make editing easier). This approach has a small disadvantage (upon renaming of a mentor, the username in GrowthMentors.json would be updated together with the next edit of that JSON page), but it fulfils the goal without potentially confusing non-tech users wondering what a mentor ID is (especially considering Special:ManageMentors is transcludeable).

Would this alternative approach (username in GrowthMentors.json as a write-only field) be sufficient for your use case, @Xaosflux?

@Urbanecm_WMF yes, though I don't think that would handle renames very well?

@Xaosflux Renames would be recognized on a subsequent edit of the mentor
list (an user quitting/enrolling, a mentor changing their
message/weight/similar, an admin removing a mentor or similar). It’s also
easy for admins to forcefully trigger an edit of the JSON page if they want
to.

Theoretically, we (Growth) can try hooking into renames and updating the
username field whenever a rename happens. Maybe we can try adding the
username field and potentially improving renames handling in the future?

In T331444#8704980, @Urbanecm_WMF wrote:

Maybe we can try adding the username field and potentially improving renames handling in the future?

That sounds like a good plan to me.

Change 900691 had a related patch set uploaded (by Urbanecm; author: Urbanecm):

[mediawiki/extensions/GrowthExperiments@master] GrowthMentors.json: Add a write-only username field

https://gerrit.wikimedia.org/r/900691

Change 900691 merged by jenkins-bot:

[mediawiki/extensions/GrowthExperiments@master] GrowthMentors.json: Add a write-only username field

https://gerrit.wikimedia.org/r/900691

Change 902734 had a related patch set uploaded (by Urbanecm; author: Urbanecm):

[mediawiki/extensions/GrowthExperiments@wmf/1.41.0-wmf.1] GrowthMentors.json: Add a write-only username field

https://gerrit.wikimedia.org/r/902734

Change 902734 merged by jenkins-bot:

[mediawiki/extensions/GrowthExperiments@wmf/1.41.0-wmf.1] GrowthMentors.json: Add a write-only username field

https://gerrit.wikimedia.org/r/902734

Mentioned in SAL (#wikimedia-operations) [2023-03-27T07:58:36Z] <urbanecm@deploy2002> Started scap: Backport for [[gerrit:902734|GrowthMentors.json: Add a write-only username field (T331444)]]

Mentioned in SAL (#wikimedia-operations) [2023-03-27T07:59:58Z] <urbanecm@deploy2002> urbanecm: Backport for [[gerrit:902734|GrowthMentors.json: Add a write-only username field (T331444)]] synced to the testservers: mwdebug1001.eqiad.wmnet, mwdebug2001.codfw.wmnet, mwdebug1002.eqiad.wmnet, mwdebug2002.codfw.wmnet

Mentioned in SAL (#wikimedia-operations) [2023-03-27T08:06:29Z] <urbanecm@deploy2002> Finished scap: Backport for [[gerrit:902734|GrowthMentors.json: Add a write-only username field (T331444)]] (duration: 07m 52s)

Deployed to production manually, as the patch should not ever get reverted (at the risk of breaking mentorship at all wikis until the username keys are removed from MediaWiki:GrowthMentors.json).

FYI @Xaosflux.