I contributed the Extension:ASHighlight extension, which allows MediaWiki to make use of Andre Simon's 'highlight' program to quickly and efficienctly produce syntax-highlighted source code within MediaWiki pages.

I also contributed some hard-won advice on restoring a wiki from cached HTML, for anyone who's dumb enough to write a wiki without checking their backup system first (like we did).

You can find my contact details maintained at http://jpye.dyndns.org