iPad iOS Firmware iPad ipsw firmware download that provided by Apple, when you do the relevant operation at your own risk.

iPad Pro 3 (12.9-inch)

iPad Pro 3 (12.9-inch) Type and Models :
  • A1876
    • iPad8,5
    • iPad8,6
  • A1895,A1983,A2014
    • iPad8,7
    • iPad8,8

The signed firmware that you can restore the file by MFC Software or by iTunes.