Unity: Reading external JSON files

I recently wrote a guide on reading external XML files in Unity. From some discussion in a Reddit post I made, I learned that Unity also has built-in support from JSON files, and there may be performance benefits to using JSON files instead of XML files. Hence, after considering to switch Mystery Queen over to using JSON files, I decided to write a parallel article — this one — about reading external JSON files in Unity. The content and structure of this article will be almost identical to the XML one, except that code snippets and some explanations have been changed.