For developers and security researchers, handling keybox.xml requires strict NDA with OEMs. The only legal way to get a valid keybox for testing is through app (which uses ephemeral keys) or by purchasing a pre-certified development board from Qualcomm/MTK.
However, calling it just a "file" is misleading. In production devices, keybox.xml is a . Think of it as a digital passport for your device's hardware. keybox.xml
Some custom ROMs use keybox.xml to trick DRM services into thinking the device has a valid L1 certificate. For developers and security researchers, handling keybox