[ajross]

That's because USB Type C is just a connector standard for a cable containing (among other things) a standard set of USB 2 and 3 signals.

[digi_owl]

Indeed. What most people refer to as USB-C is a combo of three, highly optional(!), specs.

The first is the C plug spec.

The second is the USB 3.1 protocol and cable spec.

The third is the USB power delivery spec.

All of these can be mixed and matched as the OEM sees fit.

[pat2man]

You forgot thunderbolt 3...

[digi_owl]

That one is outside of the main USB specs, piggybacking on the Alternate Mode part of the wiring spec...