Which config file is used for plugins?

I'm still working on understanding the basics of Grav... What is the file where it's defined "config.plugins.simplesearch.enabled"? I know it's a yaml configuration file, but how do I know which one it is and where it's located?

@dpdoug,

Have you had a chance to read the Configuration chapter inside the Basics section? Specifically the part on Plugins Configuration?

After you've read the basics and your question is still not answered, you might take a look at the advanced topic Environment Configuration.