[formerly_proven]

USB 3 and previous standards are completely separate connections and software stacks - the USB 1/2 D+/D- pair does not interact at all with SSRX/SSTX. You should be able to literally cut the D+/D- wires in an USB 3 cable and it should still work as a USB 3 cable.

[kevin_thibedeau]

I doubt any normal hosts will enumerate a USB device without the USB 2 data lines. PD will definitely not work. You might be able to get an alt mode running.

[cesarb]

They probably would enumerate just fine, because the SuperSpeed enumeration is completely independent from the USB 2.x enumeration. USB-PD uses a separate pin/wire, not the USB 2.x D-/D+ pair, and you cannot get an alt mode running (except the special analog audio and debug accessory modes) if USB-PD doesn't work, since alt mode enumeration goes on top of USB-PD.

[Aachen]

I'd actually be interested in a 3-only cable. Force it to use high speed or bust, no surprises, no guessing at which proto runs under the hood on that "universal" connector. Didn't know it was possible; I might make one once I've got a spare cable (just today I've got another spare but they always have just 4 cables).

More for geeky/testing purposes than to replace all my cables, but still