In the Python version pull down list on docs.python.org, Python3.5 used to be listed, but has now been removed; the list only contains 2.7, 3.6 & 3.7.

Python 3.5 is still the official Python 3.5 release in the Ubuntu repository, and still a supported release in other parts of python.org, so to see it disappearing from the drop-down was surprising.

To note - if you pick a particular page - say : 

https://docs.python.org/3/tutorial/index.html

and change the url to : 

https://docs.python.org/3.5/tutorial/index.html

The pull down now does contain 3.5 (along side 2.7, 3.63 & 3.7)