As reported by The Verge, the "CLO-001 model number" doesn't actually reveal what it is, but it is believed to be an "entirely new product". The descriptions tag it as a "wireless device" rather than a console or controller.
"The CLO-001 is surprisingly light on wireless technology — there's no 5GHz or 6GHz Wi-Fi radio and no Bluetooth, but it does sport a 2.4GHz Wi-Fi radio and a 24GHz mmWave sensor."
What could be "the most interesting detail" apparently is the 24GHz mmWave sensor, which has led to theories it could be a "radar sensor to track movement", follow gestures, or detect nearby activity.
Again, nobody seems to know at this stage what this mystery device might be, with the source also suggesting it could be something like a "new gesture control interface" or even an "upgraded dock" for a device at a place like Super Nintendo World.
Or is Nintendo returning to its "quality-of-life" initiative? If we hear any updates, we'll let you know.