Secure Element

The Secure Element (or SE) is the NFC/ApplePay chip. This chip is codenamed Stockholm. Firmware packages for the chip are codenamed Icefall and use the  file extension. Internally, the firmware packages seem to be divided into sections marked with the magics,  , and.

Apple's description of ApplePay and the Secure element: https://support.apple.com/en-us/HT203027