man pam_winbind is missing. having man pam_something is a good tradition, for example pam_stack that is add-on PAM module (not distributed with PAM itself, added by RedHat and others) has manpage too as well as the native pam_something modules.
I have added a placeholder manpage for pam_winbind
sorry for the same, cleaning up the database to prevent unecessary reopens of bugs.