You can only take this advantage with GM approval, or if it comes with a template.
Those with Second Sight can passively see things hidden by Feth Fiada.
If you suspect someone is under a Seeming, you can roll a quick contest of Per vs. Disguise. If you win, their disguise flickers when you squint at them (which is pretty obvious) and you can see through the Seeming. The only Acute Sense that benefits such Per rolls would be Acute Senses (Second Sight).
This advantage has no effect on other uses of Glamour.