This firmware file is part of the original Scratch 3.0 software (specifically for the "micro:bit" extension) but is proprietary and remains the property of the Scratch Foundation. It is only redistributed for the purpose of extension compatibility.
AmpMod currently does not make changes to the micro:bit extension in any way. Use this file at your own risk.
Please talk to a lawyer if you need more information. (We aren't one.)