edit: It seems TME beat me again. *smile*
When using a standard web-browser the saves create via the (default) eight 'Save' buttons on the Saves dialog are persisted (by default) within that web-browser's Local Storage cache.
In the case of a NW.js based application this is within the Local Storage cache of the custom Chromium based web-browser that comes embedded within the generated application, and the physical location of that cache can depend on the dataPath property of your generated application (as well as the end-user's operating system).