Valve have since deleted and re-uploaded the video with the emulator removed.
The emulator in question is Yuzu, an open source Nintendo Switch emulator.
We like the Steam Deck a lot even without having tried any emulation on it.
Valve showed a Nintendo Switch emulator in Steam Deck's library during recent video
Valve's latest Steam Deck video shows a Nintendo Switch emulator sitting in the Steam library, and Valve deleted and replaced the video.
