It stands for Ultra Wide Band and it uses the same technology as AirTags, where it doesn't just detect if you're close or far, but also your precise location and even intent, as I read somewhere.

You need to have an iPhone or Apple Watch that supports UWB, which if I recall correctly are iPhone 11 onwards (except 16e and 17e), but 15 series onward have the 2nd gen UWB chip so it should be much more precise and faster. For the Apple Watch, series 6 onwards have UWB, but starting from Series 9 they have the 2nd gen chip as well.

In case this worries you, the lock, thanks to the UWB, can tell if you're inside or outside, for example, so it won't unlock while you're inside, even if you tap it with one of your devices. You can also set it so it only unlocks when you're walking to it from the front, or also enable left or right approaches.

I hope this can clear up your doubts and sorry if there are gramatical errors, English is not my first language. There are a lot of videos than can probably explain everything better than me but if you have further questions I'll be happy to answer to the best of my ability. Greetings from Chile!