We use SourceForge to host our installation binaries and GitHub for our code repository. So. . . .
Visit https://github.com/efann/PolyJen to peruse the code in the GitHub repository.
For previous versions of PolyJen, visit the https://sourceforge.net/p/polyjen/code/HEAD/tree/ on SourceForge.
Visit https://sourceforge.net/projects/polyjen/files/PolyJen/ to browse the downloadable installations & zipped source files for various versions.
Apple OS X users
The following information contains instructions on installing and running this application.
Inside this folder, click the file with the dmg extension (e.g., PolyJen_macos_<version>.dmg).
Once the file finishes downloading, select Finder and locate the downloaded dmg file.
Now double-click the PolyJen icon in the Application folder. If you are using OS X 10.15+, you will probably see the below dialog due to new security procedures.
You should follow the below instructions to run this application for the first time.
Release the Ctrl key and click the Open button. PolyJen should now open, and you will not have to repeat the steps above until you either re-install or download an update.