You got it. That’s the project file for Movie Studio.
Do yourself a favour and practice good folder management.
I use Vegas Pro but the same things should apply to Movie Studio.
I never use the default program settings for temp file location.
I always create or modify the locations that Vegas uses.
For example, the default Temp folder is something like C:/My Documents.
The only thing on my drive C is programs and that’s it. Everything else (emails, pictures, folders for Vegas, Photoshop, etc. is on drive D or E. If you don’t have a second drive on your computer, install one (at least a 1 TB. drive). They’re very cheap these days and will make your life a lot easier when it comes time to make backups of anything. If you can’t install an internal, then use an external (USB 3 please for the speed)).
Go through Vegas and change the default locations of everything you can find.
When it comes to to new projects, create a master folder and label it appropriately.
Here’s a screenshot of a master folder for a project I’m currently working on.

This is only one example so feel free to modify it to suit your needs.
For example, I often have separate folders for music, graphics and voice overs but they weren’t needed here so I didn’t bother creating them.
Instead of clicking “Save” for a project, I always do a “Save As”, give it a specific name and version number and save it in my ProjectFiles folder. This particular one has 14 different versions because I kept making changes as the project went along. This allows me to go back to an older version I want if I’m not happy with the current one.