Metadata
In Excel, you can maintain document properties. These properties are called "metadata" in Excel. You can access them via the "File" menu and then "Info".
By maintaining that metadata, you can add information about the document, such as the author etc.
Maintaining metadata is not mandatory, but it is recommended and has benefits when searching for documents.
Clear Metadata
With the "Metadata Cleaner Button" you can delete all metadata from the App.