Xbox one x devkit or XDK is an extremely rare system! The XDK allows software creators to create, run and distribute applications on the Xbox platform.

24GB RAM vs 12GB on a Retail One X.

1TB NVMe SSD on top of the 1TB HDD from Retail.

5 Programmable Hotkeys on the front.

OLED Panel that can be programmed to display whatever a developer may want, FPS etc.

Extra USBs.

If you have any questions, let me know! It works flawlessly. You can use it in dev mode and emulate if you want or use it in retail mode and have the strongest Xbox one ever!