Comment by merb

Microsoft basically has no useful sub (sub is only useful when it comes to app credentials for Microsoft). It has oid, but if you want to support n-providers with just a login field and not a sign in with n button, than you have a problem. Or should the user know its entry lid and insert it into the username field? Most of the time you use an email and what Microsoft does in c# and their docs mean that you connect that with the oid. And also that’s why it’s stupid that Microsoft and google do not treat the email/preferred_username identifier that well. Because everybody changes the oidc spec