Use User's ID for NameID

I want to map a user’s id to their SAML NameID. Is there any way to do this? I have been using the User Attribute Mapper For NameID to map user email address to NameID. I thought this was as simple as changing the User Attribute in the mapper from email to id but that does not work. Only email, username, firstName and lastName seem to be valid values for User Attribute.

I’m not sure I understood the question – did you wish the Keycloak Username to be used as the NameID?

I am sorry if that was not clear from my first attempt to describe the problem. I want to use the ID of a user as shown in the screenshot below as NameID.