The default for this value is a sample .bat file installed in the Inventu Viewer programs subfolder "Printing" named PCLToPDF.bat.
You do not need to change this unless you want use a different command and/or utility to convert the PCL to PDF.
Sample .bat file Contents:
@ECHO OFF
REM Batch file to convert .pcl files to .pdf using Sample Open Source Ghost PCL
REM See https://www.ghostscript.com/download/gpcldnld.html and select GNU Affero GhostPCL AGPL Release 64 bit for Windows
REM Unzip to c:\program files\gs\[version] depending on the version then rename folder to "activeVersion"
REM %1 is the input .pcl file, %2 is the output .pdf file.
ECHO Converting %1 to PDF
"C:\Program Files\gs\activeVersion\gpcl6win64.exe" -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=%2 %1
