The iPhone 5 brings a lot to the table, but a lot of its changes lie under the hood away from prying eyes. Or, at least, away from those eyes until Friday when it’ll get opened up by a host of folks, including iFixit.com’s perennial new Apple hardware tear-down. The iPhone 5 has already given up maybe its greatest secret, however: A custom-designed A6 system-on-a-chip that represents the fulfillment of anacquisitionmade almost half a decade ago.