Chances are, you set up a catalog when you first installed Luminar. The catalog contains all of the information about your files including metadata like ratings and labels as well as any edits you make with the tools.
Remember, the edits you make in Luminar are always non-destructive when you work with a library. This means you are not changing the actual files but rather capturing the instructions into a database. When you are ready to share or use the file elsewhere you’ll export the image and apply the edits.
By default, Luminar’s catalog is installed in your Pictures folder. This isn’t an issue as long as you don’t include the Catalog folder when adding images. Doing this will add all preview images of the catalog to the Gallery/library.
The contents of a catalog are stored inside a folder. If backing up or moving the catalog, be sure to take the entire folder.