I didn't know if that "*" was part of python, or just specific to the documentation.

I started by just looking around the page (header, section on the left and footer) for some kind of link pointing to how to interpret the documentation.

Not finding anything, I went up the tree (first to https://docs.python.org/3/library/index.html , then to https://docs.python.org/3/index.html ). I then went to the FAQ ( https://docs.python.org/3/faq/index.html ).
(Little did I know, the answer was in Glossary...)

Not finding any answer there, I tried googling it (simply starting with "python *"), but since * is interpreted as a wildcard, my searches only gave broad results about "python".

I then asked a friend who pointed me to https://stackoverflow.com/questions/51362773/what-does-mean-as-a-parameter-in-python