You can use Subversion clients and some Subversion workflows and properties with GitHub.

What are the differences between Subversion and Git?

Subversion (SVN) repositories are similar to Git repositories, but there are several differences when it comes to the architecture of your projects.

Support for Subversion clients

GitHub repositories can be accessed from both Git and Subversion (SVN) clients. This article covers using a Subversion client on GitHub and some common problems that you might run into.

Subversion properties supported by GitHub

There are several Subversion workflows and properties that are similar to existing functionality on GitHub.