Jatex is currently not stable nor suitable for actual use. When that time comes this page will be useful and have the package in distributable forms.
In the mean time, you can look at the code either by browsing the SVN repo or by checking out the code. If you do so, please submit feedback/bugs.
svn co https://jatexeditor.svn.sourceforge.net/svnroot/jatexeditor/trunk jatex