Maybe you are asking the wrong question?
Perhaps you could clarify
why you’d even need that file.
It sounds like you want to do some configuration to the program you have installed.
config.h and other files are in the source code of that application
The source code is only needed if you want to completely build the program “from scratch” yourself.
It’s not included with the thing you have installed right now.
Do you want to compile the program?
Or do you just want to configure how it behaves?