AADB2C: include username in JWT claims
AADB2C supports either email addresses or usernames for accounts. If a directory uses usernames, you don't get that username as a claim in the JWT. This means an extra trip to Azure must be made to retrieve the username. Please consider including the username in the JWT.
This is currently not on our roadmap. You can retrieve this value by making a call through the Graph API. If this is needed for your scenarios, please continue voting and we will review at a later date.
Kevin Ortman commented
Why allow UserName to be a first class IDP citizen without providing it's value in the JWT claim?
I've reluctantly reverted to EMail to avoid the extra hop required to extract that claim.