This thread has been very useful.
Shame I only found about it by accident, it's rather hard to find for those who need this information.
In my opinion, the product page for 6ES7901-4BD00-0XA0 should definetly have some of this information there.
I have the mentioned cable, but it has recently broken. I opened the metal side of the cable, and was confused by the circuit board there. Since I thought the cable was a simple profibus cable, like the product page says, and since the metal end looks somewhat "unfinished", with one empty hole for additional cable, I actually thought this was some custom made cable, made by person unknown. Specially since the picture on the product page shows incorrect cable.
I even asked my local Siemens office, and they claimed that since my cable has a metal end, it can't be original 6ES7901-4BD00-0XA0, since it has 2 integrated plastic ends. They were of the opinion that this was a custom made cable, made by some earlier employer in my company. After submitting a picture of my cable to them, they chanced their minds, and said:
"It indeed seems to be an old Siemens cable. It's propably from a time before the name Profibus was taken to use. I think it was named L2 bus at the time."
(Text translated from Finnish). However, this indicates that the incorrect picture and the missing information on the product page is affecting even Siemens staff.