I fear that the very oldest information about Python, back in 1991, is probably now lost forever.
You should look at Guido’s blog at Artima:
You will find some very significant jewels buried there, such as the beginnings of annotations and type hinting.
Although it came quite late in Python’s evolution, you can look at Brett Cannon’s thesis.
Another good place to start is to go trawling through the oldest Python mailing list archives. I think that “Python-List” is probably the oldest, it goes back to 1999.
Okay, that’s three URLs, as many as I dare. I believe that Discuss does not like it when you post too many URLs in a post, especially from email. So from this point on I will tell you how to manually visit a URL rather than just give a link.
(Sorry for the inconvenience, I would give URLs if I could, but I fear that Discuss may just silently flag me as spam and discard the post if I do.)
Python-List is mirrored on Usenet, under comp.lang.python, so if you happen to have access to an archive of c.l.p going back to the 1990s, you may find some good information there. You can try the Google Groups mirror.
Other significant mailing lists for the evolution of Python are Python-Ideas and Python-Dev. They have been migrated to Mailman3 with the Hyperkitty interface, but for undirected browsing, I find the old pipermail archives much nicer. (YMMV.)
Take the above pipermail URL and manually change the “python-list” fragment to “python-ideas” and “python-dev” to visit those mailing lists as well. From there, you will have the old pipermail archive, as well as a link to the Hyperkitty archives.
If you go to the mail.python.org domain in your browser, it will redirect to a list of all all the Python mailing lists.
I could have sworn there was once a dedicated Python3000 mailing list specifically for discussing the Python 2 to 3 transition, but I can’t find it now.