uFileBrowser is a sample app to exercise the Storage APIs and also the broadFileSystemAccess restricted capability. The app must ask the user for permission to access the filesystem broadly. Without this permission, the app will only be able to access the standard file locations that any UWP app can access. With the permission, the app can access any location that the user can access, without further prompting. The user can grant or deny permission at any time by going to the Settings app, in the Privacy section, under the File System tab.
On first launch, the app will show a dialog that prompts the user to go to the Settings app to grant File System permissions. In order to use the features of the app, you should accept this request (the user can always change their mind later by going to the Settings app | Privacy | File System). If the user changes the settings while the app is running, this will terminate the app so that the new permissions can be applied.
See here for further information:
https://aka.ms/AA63o4w
https://aka.ms/AA63o4y
Sample source code on GitHub here:
https://aka.ms/AA63h3o
