Gerrit

Gerrit is a web based code review system, facilitating online code reviews for Wikimedia using the Git version control system. For MediaWiki core development and Wikimedia-deployed extensions, commits must be reviewed before being merged into the master branch.

Getting started
Wikimedia's Gerrit installation is located at https://gerrit.wikimedia.org/. If you have developer access, you can participate in the review process, but only core developers can merge changes. Git/Workflow gives a full overview of the Git/Gerrit workflow.

Tutorials & guidelines
Useful documentation written for MediaWiki & Wikimedia developers:

Advanced usage:
 * Git and Gerrit tutorial
 * Commit message guidelines
 * Gerrit web interface navigation
 * /resolve conflict/
 * /mass approval/
 * /split a submitted change/
 * /watched projects/
 * /personal sandbox/
 * /workflow/ops/
 * /Project ownership/

Miscellany

 * List of the public Gerrit projects
 * Stats (not very useful at the moment)
 * Technical information about Wikimedia's Gerrit installation
 * Report bugs/other issues with Git or Gerrit