Douglas Wright added the comment:
The links are working now.
I recall that all of the links in that section pointed to different URLs on 3.9
and newer than they did on 3.8. On 3.9 and newer, you would land on "page not
found" on readthedocs.org.
They all seem to match up
New submission from Douglas Wright :
Links in this section from the docs from 3.9 and newer are currently broken.
https://docs.python.org/3.9/distributing/index.html#reading-the-python-packaging-user-guide
They are currently leading to a "page not found" error.
--
assi