We have ~24 users (select distinct gu_name, count(oad_id) from oathauth_devices JOIN globaluser ON (oad_user = gu_id) where oad_type = 2 and oad_created <= '20250328000000' and oad_created >= '20250318000000' group by gu_name; see also {T401742}) that seemingly have WebAuthn enabled on a local domain, and need to ask them to disable their device, and re-enroll it on the central domain.

Emailing them directly from a WMF email (can probably just be a staff email) is sufficient... But need to write some text to send them, and possibly give a deadline for when this may stop working for them..