I believe they would have removed the redundancies of the releases as they were all the same install file anyway and just labelled them under the one link for each version number.
If you click in on one of the links e.g. Ruckus IoT 1.3 (GA) SZ Software Release (.ova) (vSZ-E, vSZ-H install image)
these would include for a fresh install and it is an .ova file for virtual box. The .ximg files are for upgrading your vSZ\SmartZone to support IoT if you are running an older version of vSZ\SmartZone.Ruckus IoT 1.3 (GA) SZ Software Release (.ova) (vSZ-E, vSZ-H install image)
Ruckus IoT 1.3 (GA) SZ Software Release (.ova) Virtual SmartZone.
VM Platforms: VMware ESXi 5.5+, VM Player 12+, Oracle VirtualBox v5.1.20+, Google Chrome v61+, Mozilla FireFox 56+, Safari: supportedFilename: vscg-22.214.171.124.13022.ova (for new/clean install)
What version are you after as well, I might have something lying around from a while back.