In SVN, SyntaxHighlight had an external for geshi/geshi.php and friends. This is gone in git, so out of the box I now get:
Warning: require(geshi/geshi.php): failed to open stream: No such file or directory in /home/catrope/mediawiki/git/extensions/SyntaxHighlight_GeSHi/SyntaxHighlight_GeSHi.class.php on line 376
I fixed this by copying the dir over from my SVN checkout, but this should be fixed properly somehow.
Roan