Tmux just switched its VCS from CVS to SVN. I don't see why anyone who decides to switch away from CVS today would choose subversion. I suppose the high convergence between CVS and subversion workflows could be a reason for long time CVS users.

Anyway. I didn't want to bash anybody's choice of version control when I started this article. What I really wanted to say is that...

% git svn clone https://tmux.svn.sourceforge.net/svnroot/tmux/trunk tmux

...will get you a git import of the subversion history. And yes, you can update that import incrementally using:

% git svn rebase

If you want to do actual development in that import, that's possible, but you may want to take a look at git-svn's documentation.