The SwingSet demo didn't work at all for me on Linux. (I'm running fully patched Garuda KDE on x64, which is basically arch.)
The build number refers to your app version. The download page creates the bundle on the fly (but does cache) using the latest jDeploy release, so when I released the new version of jDeploy, the bundles in the download page are auto-updated. I thought of adding the jdeploy version number into the installer name, but it was getting pretty busy already, so I decided to just leave that off.