Why doesn't OS X Spotlight search inside .json files? I am trying to search a folder for an ID number. The folder contains various different file types. The ID can be found in several .json files, but non of them show up. 

If I rename the .json file to .json2 or .jsont then the files show up in the search:


If I try and use terminal and mdfind it is the same, .json files wouldn't show up when searching for the ID.

Is there some setting I need to change such that spotlight/mdfind will search inside .json files? Or will I have to rename all files?

Note: Some of the .json files are quite large (~16 MB). Does this matter?
You could try adding JSON to the Spotlight RichText importer.  The process for XHTML is described here, and should be analogous for JSON:

http://lists.w3.org/Archives/Public/www-archive/2013Jun/0079.html