Do you have a source? I looked for a while and couldn't find anything except ones that say it supports data, just usb 2.0 speeds.
> Compared with Apple USB-C Charge Cable The Apple USB-C Charge Cable is longer (2m) and also supports charging, but data-transfer speed is limited to 480Mbps (USB 2.0) and it doesn't support video. The Apple Thunderbolt 3 (USB-C) cable has Thunderbolt logo on the sleeve of each connector. Either cable can be used with the Apple USB-C Power Adapter.