[supercoffee]

Some of the Drop branded keyboards like the Alt have a USB passthrough. I used to own one and I used it to plug in my headset dongle.

[Findecanor]

The Drop keyboards merely have two upstream ports, so you can select to have the cable on the left or on the right.

There is no hub. If it was passthrough, the cable would be fixed (or use a non-standard connector), with two USB plugs at the host end: one for the keyboard and one for the passthrough. Some older gaming keyboards have such passthrough for USB ... and audio jacks!