Is a USB cable for data, or only power; how to tell without testing it?

Short of testing a cable, is there a way to tell by looking if a USB
cable is data/power or power only? 

Is there a logo or a mark on the plug or wire?    

If not, why not?  Do they want to drive us crazy? 



Sort of separately, I found a cable on the street, white, good condition
everywhere, USB-A to USB-C, well-made, and on the USB-A end is written 
PISIGMA. 

But when I first looked at the writing, I could only read it, most of
it, upside down, and it started with VW.   So I looked for VW ISI cable,
and I found: 
https://parts.vw.com/p/Volkswagen_2021_Atlas/Media-Cable---USB-C-to-USB-A-Adaptor/90354124/000051446BD.html
   This 70 cm USB cable (USB-C® to USB-A Adapter) is designed to connect
   a smartphone or other mobile device to your Volkswagens Infotainment
   system. This premium cable features silver connectors with an 
   embossed Volkswagen logo.  [It's silver on the outside. I don't think
   the connection places are silver plated.]
   Proper installation required. Professional installation may be   
   recommended. See owners literature and dealer for details. 

and the same thing at  
https://www.amazon.com/Volkswagen-000051446BD-Connection-Adapter-Premium/dp/B08K67W8G2/ref=sr_1_32
Volkswagen 000051446BD Connection Data C to USB-A Female Adapter Premium
Cable 70 cm, Silver 
Original VW premium connection cable USB-C to USB-A socket with
Volkswagen logo.
100% Volkswagen original accessory.
Interface: USB-C to USB-A female angled
Colour: black, silver.
Length: 70 cm. 

$50 and $46, plus delivery.   How do they have nerve enough to charge 46
dollars for a 2-foot cable? 


Ah, I found it,
https://pisigmainc.com/collections/charging-cables/products/type-c-charge-data-cable-1-ft
Despite url saying 1-ft, it's really 1.5 or 3meters and it sells for
$9.99.   At that price, it must do data too, oh, and it says it does.