welcome! talking about the first layer printed, with the so called "metalic" line, that they only need to make a common copy, to detect forgery, because it doens't appear on the copy, its because of the ink . the ink must be " Electrically Conductive Inks – Carbon The ELECTRODAG line of carbon inks includes products for PET film, plastic film and paper substrates, membrane touch switches and rigid printed circuit boards.", because a very high security features they print over on the first layer, which is the figure, this is an electronic detection (still don't know if GPS incorporaded...) , the print of that stripe is, one line, up, and one vertical down...

https://www.google.com/patents/US8540812

https://www.google.com/patents/US20030059987

https://www.google.com/patents/US20140116474