There is no handshake, all that's needed are two 5.1 kΩ pulldown resistors. By omitting them the manufacturer saved all of about 0.1c and made their device incompatible with compliant usb-c chargers.

More info: https://hackaday.com/2023/02/07/all-about-usb-c-manufacturer...

Such products shouldn’t exist by spec, they’re just not compliant.