@Ron The JSON file is plain-text and human-readable in the same way that HTML or RSS is human-readable—there’s the text, inside of various structures marking up the text, with certain characters encoded. Any program you have that can open plain-text files and has a find function will allow you to search the file.
This is what I do, simply keep it as an archive (replacing it periodically with a new download) and then search it, but if you wanted to make it more human-readable, I am sure there are tools out there that can turn a JSON Feed file into regular HTML or something.