This folder configures the Content Parsers that Search Boost diplays in the settings page for users to enable.
A content parser is basically an association created between one or more file extensions and a class that implements IContentParser.
This means you can extend Search Boost to index new file types by creating your own class that 
implements IContentParser (link to DnnSharp.SearchBoost.Core.dll) and then add it to a Json file simillar to ".defaults.json.config".
Whenever you change this files, if changes are not instantly visible in the amdin console (which should happen automatically), 
please restart the application.

.defaults.json.config contains the default content parsers. Do not change this file as it will get overwritten on upgrades. 
Instead, create your own Json files simillar to .defaults.json.config that contain the nodes you want to override.

For example, to add your own content parser for extension xlsx, create a new Json file, say MyContentParser.json that looks like this:

[
    {
        "Id": "ExcelDocuments",
        "Title": "Excel Documents",
        "TypeStr": "Fully.Qualified.TypeName, MyAssembly",
        "DefaultOn": false,
        "Extensions": [
            "xlsx"
        ],
        "MimeTypes": [
            "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
        ]
    }
]