To run the xemu emulator, you need specific system files that are not included with the software due to legal and technical reasons. These files are used to boot the emulated console and bypass original hardware DRM. Required System Files
However, I can explain the interesting feature you mentioned, plus exactly which files you need and how to get them legitimately.
However, unlike emulating a SNES or a Game Boy, getting Xemu to run is not plug-and-play. The single biggest hurdle for new users is understanding and acquiring the Xbox BIOS files.
Not every Xbox BIOS will work perfectly with xemu. For the best compatibility and performance, the community generally recommends the following:
MCPX Boot ROM: The internal "handshake" code used during the boot sequence (usually mcpx_1.0.bin).
Date: October 26, 2023 Subject: Analysis of BIOS File Requirements for the Xemu Original Xbox Emulator Prepared For: General Users / Technical Documentation
: This is a tiny (512-byte) file used during the initial boot sequence. The most compatible version is mcpx_1.0.bin Flash ROM Image (BIOS)
In the context of emulation: