If your selected Shape Layer Type is KML, this field can be used to provide a URL to the KML Style file separately from the KML URL. 

In most cases, KML Style URL can be found by opening the main .kml file in a text editor (for example, Notepad) and using the search function (Ctrl+F) to find a string that contains the tag <styleURL>. The link between these tags is the KML Style URL, which you can paste into this field to apply the style properties for the shape layer.

The URL must be a direct link to the .kml file and it must be hosted on a web resource that supports Cross-Origin Resource Sharing (CORS) headers. For example, Google Drive, Dropbox, and SharePoint are not supported as these services do not support CORS for use with this visual.