Thanks to all.
You helped me clarify the question I need to ask of cable and device makers/vendors.
The Wikipedia page on USB Hardware, in the section on charging has the details alluded to above.
https://en.wikipedia.org/wiki/USB_hardware#cite_ref-57
So many details don't get presented on consumer goods, or are even made hard to find.
It's easier when you get to a good/the right question and know where to look.
Thanks again