When you press Ctrl+S to save the work/project file, you will get a file in .WVE format. It is not a video format file, it’s the exclusive file ended with .WVE which stores memory of all related elements used and editing decisions made for one movie on the Timeline. If you delete some of the original files, or move, or rename them, the project file will be damaged and can’t be opened. And it could be recognized only by Filmora, you can reload it by clicking OPEN RECENT for further modification.
To avoid losing the project file by accident, it is suggested to archive the project file. Then if part of the original files of the project file are moved, deleted, or renamed, you can also open the project. You could click here to check the tutorial.