User blog comment:Marioworld/Question/@comment-4018164-20121212094127

There are 2 ways to find unreleased items:
 * 1) Searching files one by one by ID: This way takes much more time than the first way, but would usually allow finding files that do not appear on the second way. It's done by going to the latest SWF files (for example: Clothing icons (random link)). If you are looking for clothing swf, note that every thausand files, there will be for a different clothing type (+1000 for head items, +9000 for backgrounds, etc.). t note that some mascots items only exist in the sprites folder, and sometimes even in the paper folder.
 * 2) Searching in JSON files: JSON is a special script, that is very simple in its structure and doesn't take much time to read, like in other files. What JSON files do, is to store data, and CP uses a variety of them. We have a Special Page for a list of JSON pages. You might want to see the Clothing or the Rooms files, as tehy are mostly used. You can use Ctrl+F to search for a particular item ID or room ID or name to look for many data about it (item price, room music, room ID, etc.). Another useful page is the Action frames file. It tells the server in what combination of clothing you can do special dances, so by looking at a line with the ninja mask, for example, you may find Sensei's clothing items. For more JSON files, you can go to the wiki's JSON list page.