Network discovery gateway connects to remote machines and runs a scan to get various information, one of them is the applications installed
How are the "Applications" installed detected by NDG?
Within the registry hive of: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
For each item that has "DisplayName" and "Version", those applications are considered installed and will be used within the results
A Microsoft patch is also detected here using the same keys, but validates that the Publisher is "Microsoft" and that the "DisplayName" contains "KB" in order for it to be a Microsoft KB Patch
Each distribution has its own command for this
|HP-UX||/usr/sbin/swlist -l product|