It seems they are one and the same package but with different names. if they are the same, can't gnome-extra/libgail-gnome go away from portage ?
Not to my knowledge, although i'm not certain of their exact uses. But a simple comparison shows enough differences to rule out they are one and the same thing, something which you couldve assessed by yourself I'm sure. Make sure there is a real problem when posting a bug please, every bug takes up a bit of our already limited time.