You can for example compare my repo master branch with that available from wikimedia https://github.com/magul/pywikibot-core and https://github.com/wikimedia/pywikibot-compat (oops it looks like wikimedia mater has been changed again, and my master is up to date with wikimedia master). The difference starts at march 21th, I guess it's the time, when wikimedia make pywikibot's git repository publicly available.