Summary

StartExeWithWorkdirAndOutput.exe expects only the file path of an executable as argument. For example, if you call StartExeWithWorkdirAndOutput.exe C:\dev\test.exe, it will set "C:\dev" as the working directory and redirect the output of test.exe to your caller.

But why?

I wanted to run a executable from an Editor for my custom programming language, but I couldn't find a way to call an .exe file with its working directory and simultaneously capture the output in Godot.