It's included with Windows, but it's not the default for most (any?) of the file types it can handle any more-- the Movies & TV Store app opens video files, an

It's included with Windows, but it's not the default for most (any?) of the file types it can handle any more-- the Movies & TV Store app opens video files, and Groove Music opens audio files. So it's not really in the path of most users any more; it's still there for people who know about it, but you're not likely to run into it unless you go out of your way to use it.