( New York Times ) – Since the pandemic’s early days, China has used mobile apps to identify and isolate people who might be spreading Covid-19. Now, a central Chinese city may have shown a far more troubling use of that data: stopping would-be protesters. Dozens of people from across China had set off for the city of Zhengzhou days ago to protest the freezing of their savings amid an investigation into several regional banks. But when they arrived in the city, many found that the so-called health codes on their phones had turned from green — meaning good —...