Dear Moderator,
I would like to pay your attention on header of my question. It is “Maximum allowed internal temperature…” , rather then
" Operating temperature" (defined by WD to be 5°C to 35°C). I definitely have downloaded “Specifications for the My Book external hard drive” from your site. It was a first thing I searched on WD site, by the way. It did not help.
On the other hand, there is one more definition in this document and it is “Non-op. temperature: –20°C to 65°C”.
It is not very understandable definition, but one might consider, that in the room with 65 degrees My Book will not work.
All this is not what I asked for!
As you can know, there is some difference between external (environment) temperature and internal temperature inside a disk, as well, as another one inside an enclosure.
Software, for example, Hard Disk Sentinel, measures not a room temperature, but rather one inside a disk 
A maximum value have to be set in this program, in order to send an alert, if disk go too hot.
So, one more time. What is a maximum allowed internal temperature - one, software can read from a disk controller, for My Book 4TB disk?
One of possible answers might be “It is the same, as environmental operating temperature in product specifications”, but it does not make sense. 35 degrees is too low value…
Hope to get an answer.
Regards,
Valery