This makes it the plugin useful for any form of webserver-based
authentication (CAS, SAML, etc.); of course, other plugins will
have to be installed to handle connections to the IMAP/SMTP
servers, but at least they don't need to duplicate the basic
HTTP authentication functionality.
This is useful if the users are free to choose arbitrary mail hosts (or
from a list), but have one host they usually want to log into.
Otherwise the username/password must always be typed in twice.
is authenticated is assigned to 'login' task instead of 'mail'. Now binding
plugins to 'login' task is possible and realy usefull. It's also possible
to bind to all tasks excluding 'login'.
nicolas-joubert