WAA suggesting user name
A brief description of what is proposed
An addition to the webauth protocol to allow the waa to suggest (or mandate) a user name for the user to use.
An explanation of how it would be useful
There are circumstances (my Raven/OpenID bridge being the only one that comes to mind) where a WAA knows that there is only one user name that will be a satisfatory response to an authentication request. In these circumstances, the user would be helped if Raven presented them with a login box with the user name already filled in. It might even be reasonably for it to prevent the user changing the user name, but I think that would probably cause too much confusion.
One or more suggestions of how it could be implemented
An additional parameter added to the authentication request:
principal [OPTIONAL] If present, indicates a suggested identity to offer the user. The WLS MAY use this to seed a login form.
This would also require a change to the ver parameter.
Raven would seed the "User-id' box with the supplied identity, in the same way as it usually does from a cookie, arranging to put the input focus in the password box if possible. Otherwise, its behaviour would be unchanged.