<PackageReference Include="System.Security.Permissions" Version="11.0.0-rc.2.26504.105" />

System.Security.Permissions.IsolatedStorageFilePermissionAttribute

Allows security actions for IsolatedStorageFilePermission to be applied to code using declarative security. This class cannot be inherited.
namespace System.Security.Permissions { public sealed class IsolatedStorageFilePermissionAttribute : IsolatedStoragePermissionAttribute { public IsolatedStorageFilePermissionAttribute(SecurityAction action); } }