Getting information from a cfg file

I have notice in many games but most recently in kerbal space program (made in unity) that they are using cfg files in an external folder from the project folder. (If that makes snense).

My question is:

Is it possible to get information from a '.txt' or '.cfg' file that isn't 'inside' the project upon building for a script within the project.

Any help is appreciated

I understand my explanation may be somewhat confusing so if you have any questions feel free to ask away