Ciro Santilli A 2022 clone of phabricator.wikimedia.org/source/mediawiki.git gives first commits from 2003 by:
- Lee Daniel Crocker: en.wikipedia.org/wiki/Lee_Daniel_Crocker
He is best known for rewriting the software upon which Wikipedia runs, to address scalability problems.
so that gives a good notion of the last major rewrite. - Brion Vibber
TODO when was wikipedia open sourced from Nupedia? The ealry days of Wikipedia are quite obscure due to its transition from Nupedia.