Here's the question on SO :
http://stackoverflow.com/questions/42988225/ios-dropbox-api-how-to-tell-folders-from-file-packages
Thanks for reaching out, Ben. Seems like the answer on StackOverflow is probably more than I could offer you. As the reponse there says, the best fallback approach would be to have a has-a-filename-extension check to manually catch all your bundle types.