Username for external authentication
When somebody is authenticated by a service external to the site,
this field contains the identifier for the account on the remote service.
It is possible for a person to have several remote usernames stored in
Mahara, but each one must be associated with a different external
authentication method.
The current rules for the update of this field are as follows:
- If you wipe the contents of this field and submit your changes,
the external username associated with the selected authentication
method will be reset to the default username.
- If you update the contents of this field, the external username
will be reset for this authentication method, or a new one will be
created if it doesn't exist yet.