Comment 5 for bug 345344

/usr/include/glib-2.0/glib/gi18n.h:
#define N_(String) (String)

Indeed those string are left untranslated.

static const gchar * title_strings[LOGOUT_DIALOG_ACTION_CNT] = {
 /* LOGOUT_DIALOG_LOGOUT, */ N_("Log Out"),
 /* LOGOUT_DIALOG_RESTART, */ N_("Restart"),
 /* LOGOUT_DIALOG_SHUTDOWN, */ N_("Shut Down")
};

static const gchar * restart_auth = N_("Restart...");

static const gchar * body_logout_update = N_("You recently installed updates which will only take effect after a restart. Restart to apply software updates.");

static const gchar * singular_strings[LOGOUT_DIALOG_ACTION_CNT] = {
 /* LOGOUT_DIALOG_LOGOUT, */ N_("Unless you cancel, you will be logged out in %d second."),
 /* LOGOUT_DIALOG_RESTART, */ N_("Unless you cancel, the computer will restart in %d second."),
 /* LOGOUT_DIALOG_SHUTDOWN, */ N_("Unless you cancel, the computer will be shut down in %d second.")
};

static const gchar * plural_strings[LOGOUT_DIALOG_ACTION_CNT] = {
 /* LOGOUT_DIALOG_LOGOUT, */ N_("Unless you cancel, you will be logged out in %d seconds."),
 /* LOGOUT_DIALOG_RESTART, */ N_("Unless you cancel, the computer will restart in %d seconds."),
 /* LOGOUT_DIALOG_SHUTDOWN, */ N_("Unless you cancel, the computer will be shut down in %d seconds.")
};

Why are those strings left untranslated?