With the "normal" audio USB cables, there is only one conductor strand. This strand contains the two data lines D+ and D-, the +5V supply voltage and the ground (0V).
I'm a little annoyed that I didn't think of it first, but in fact the idea of the "dual head" came about as a result of dealing with the issue of "unnecessary ground connections".
The USB signal (Universal Serial Bus) is differential. The data is transmitted via D+ and D-. Thus, no ground connection between transmitter and receiver is necessary in a "domestic environment".
Shielding is superfluous for a balanced signal under normal conditions. However, if you operate an MRI next to the music system, it's a different story.
The cable has two USB-A plugs for the source. One connector transmits the data, the other the voltage or current. The 5V voltage is only needed so that the DAC knows that a transmitter is connected. You can plug both USB-A plugs into two free slots on your streamer. Or you can plug the power supply into a commercially available USB plug-in charger ... and get rid of the ground reference between the two devices. Or even better: use a linear power supply (the ones with a real transformer).
AES/EBU Digital Cable
Interestingly, sometimes not used, although the possibility would exist. AES/EBU is clearly better than S/PDIF ...
... because AES/EBU is differential. The characteristic impedance is set exactly to 110 ohms.
Is superfluous with a balanced signal under normal conditions.
With a balanced signal, a reference to ground is unnecessary. Therefore, this cable has no ground connection.