aka fixing bug, sending patches example : kdevplatform
- clone :

git clone kde:kdevplatform

- branch :

git checkout -b bugfix

- dev & tests
- commit :

- git format-patch 

sending patch to git.reviewboard.kde.org :
- from bugfix branch :

post-review --parent=master

- or better, upload a git-format signed patch on reviewboard, because post-review will lost the 'author' info.

more infos :

:: http://en.flossmanuals.net/kde-guide/
:: http://techbase.kde.org/Development
:: http://techbase.kde.org/Development/Git
:: http://techbase.kde.org/Development/Review_Board