Solution
The GSDML file to be imported into your PROFINET IO-Controller configuration tool for the CompactRIO PROFINET module (cRIO-PN-S in short) by KUNBUS GmbH is included in its driver package. The driver is called
cRIO PN by KUNBUS GmbH. The most convenient way to install it is through VI Package Manager using this
direct link.

After installation is finished, the GSDML file is available on your computer in
C:\Users\Public\Documents\KUNBUS GmbH\GSDML similar. The file's name format is
GSDML-V[x.x]-Kunbus-cRIO PN-[yyyymmdd].xml.