Hello,
As was mentioned many times on the list, PEP634-PEP636 are thoroughly
prepared and good materials, many thanks to their authors. PEP635
"Motivation and Rationale" (https://www.python.org/dev/peps/pep-0635/)
stands out among the 3 however: while reading it, chances that you'll
get a feeling of "residue", accumulating a section over section. By the
end of reading, you may get a well-formed feeling that you've read a
half-technical, half-marketing material, which is intended to "sell" a
particular idea among many other very viable ideas, by shoehorning some
concepts, downplaying other ideas, and at the same time, light-heartedly
presenting drawbacks of its subject one.
Just to give one example, literally at the very beginning, at the
"Pattern Matching and OO" section (3rd heading) it says:
Pattern matching is complimentary to the object-oriented paradigm.