Comment 2 for bug 1906960

About the first issue I created a small script to check the dimension of the problem. There are 477 locales in my system (only selecting utf and iso), of those 41 are affected by the change of %OB from %B.
On about half of those the change is to lose the article (for example in catalan an what I would intend to accomplish). So about twenty of the locales (being russian and polish the most popular) have other changes (maybe someone from that community should comment on this)

---------------------------------
#!/bin/bash
echo -n '' > /tmp/b
echo -n '' > /tmp/ob
for L in `locale -a`; do
        LC_TIME=$L date +"$L %B" >> /tmp/b
        LC_TIME=$L date +"$L %OB" >> /tmp/ob
done
diff -y /tmp/b /tmp/ob --suppress-common-lines | grep -E "(utf|iso)"
---------------------------------

About 2), there's a ticket opened by myself a few months ago commenting that missing part in the documentation, you should be able to call it even if it's undocumented on most version. See it here (https://bugs.python.org/issue38228), stating the same more or less (when there's no ab_alt_mon or alt_mon defined it will return the normal values)