Singapore has shared their contact-tracing app with Japan, South Korea and Taiwan. (I am not sure if China developed their own contact-tracing app or not.)
You’re not so familiar with the ways of a totalitarian regime such as China? Knowing who you are, where you are, who you’re meeting, what you’re saying and what you’re thinking comes as standard. And if you don’t patriotically cooperate with the authorities in this by carrying a phone on which location services can’t be turned off, you quickly get into a lot of trouble.
All enabled and supported by tech given away by - Google.