SDX57M

The Qualcomm Snapdragon X57 5G Modem is the baseband chipset used in the iPhone SE (3rd generation).

it is also known as  in firmware.

Known Firmware Versions
1.00.04    15.4           (Build 19E241) 15.4.1        (Build 19E258) 1.60.00    15.5 beta      (Build 19F5047e) 15.5 beta 2   (Build 19F5057e) 1.61.01    15.5 beta 3    (Build 19F5062g) 15.5 beta 4   (Build 19F5070b) 15.5 RC       (Build 19F77)