DF 2.3 username Field

I noticed in DF 2.3 the user now has a field called 'username'.

This is exactly what I need. Unfortunately there is no access to it via the user service, only system service can access it. Is this not completed yet? Will it be in a future version?

It would be great if user/register could set the username and GET on user/profile and user/session returned this field.

Thanks for the great work.