Answer for File name

What is this in reference to?  Is it about this?

How to Stream Kodi to Chromecast, Xbox One, DLNA Devices

There is really no telling what video file type is produced by this process.  This process doesn’t produce a certain file type.  The file type is whatever it was originally saved as when it was stored on the streaming server.  So, the type could vary.
That’s why sometimes it works, and sometimes it doesn’t.