Both the Xbox 360 and the Xbox One/Series are using emulators to run OG Xbox games. Its called Xefu (Xenon Fusion Emulator).

Just having a x86 CPU doesn't mean console generations are interchangable.

So to answer the parent comment, yes, it's emulation.

It does work on the steam deck, but you'll need to source a copy from somewhere as its not sold on steam.

Hmmm

Why wait to play on a switch emulator when you can play it on an Xbox 360 emulator now? (Xenia Canary)