The WordPress core development team builds WordPress! Follow this site for general updates, status reports, and the occasional code debate. There’s lots of ways to contribute:
WordPress uses Subversion (SVN), a very popular version control system managed by the Apache project, to manage changes to its codebase. A change to the WordPress codebase increments the revision number. Individual changes are called commits or changesets. These are denoted as either r12345 or [12345]. Details of the SVN and Git repositories are located here.
The WordPress repository of code is organized into three main directories: tags, branches, and trunk.
The trunk directory contains the latest development code in preparation for the next major release cycle. The latest revision may be unstable or broken at times. The latest development code may be referred to as trunk.
The tags directory contains individual snapshots of each official release, such as the 3.4.0 or 3.5.1 tags. Once created, these are unmodified, and these are used to build the download packages.
The branches directory contains directories that consist of the latest code for each major release, such as the 3.4 and 3.5 branches. Minor release development occurs within the branch. For example, a critical bug that affects the latest release may be fixed in both trunk and the most recent branch, in preparation for a point release – i.e. 3.5.2, in the case of the 3.5 branch. These should generally be considered stable, but care should be taken when a minor release is being prepared.
Many developers run SVN commands using the command line interface (CLI), such as Terminal on the Mac. Even though most basic commands are simple, the command line is reasonably intimidating for many users. Many developers do rely on GUI applications though, either for regular use, or to handle complex actions more effectively.
For Windows, the recommended SVN client is TortoiseSVN, which is free and open source.
For Mac, the recommended SVN client is Cornerstone, which must be purchased.
