https://learn.microsoft.com/en-us/uwp/api/windows.applicationmodel.appextensions.appextension.getpublicfolder?view=winrt-28000
AppExtension.GetPublicFolder Method (Windows.ApplicationModel.AppExtensions) - Windows apps |...
Gets the subfolder provided by the PublicFolder attribute in the app extension for sharing files between the extension and the host.
methodwindowsapps