$ /Library/Application Support/TextMate
$ svn co http://svn.textmate.org/trunk/Support
For example, after updating the Ruby Bundle I got this error:
run_script.rb:1:in `require': no such file to load -- /Applications/Editors/TextMate.app/Contents/SharedSupport/Support/lib/tm/executor (LoadError) from /Users/user/Library/Application Support/TextMate/Bundles/Ruby.tmbundle/Support/RubyMate/run_script.rb:1
For more information about Bundles see the
Textmate site. Credits: http://lists.macromates.com/textmate/2008-September/026802.html