Here is the professional breakdown of the software, its current status, and how to obtain the correct version.
Ubiquiti has replaced the outdated discovery tool with much more robust utilities: For Desktop (Windows & macOS): WiFiman Desktop ubnt discovery 2.3 download software
Disclaimer: Version 2.3 is quite old. If you are managing modern UniFi devices (Gen2/Gen3), it is recommended to use the Ubiquiti WiFiman desktop app or the UniFi Network Controller instead Virtualization Howto Discovery Tool v2.3 broken with OpenJDK Java 7 Runtime Here is the professional breakdown of the software,
No Longer Maintained: Ubiquiti removed the tool from its official downloads and the Chrome Web Store. its current status