@Nullable
    public static Folder fromFolder(final Folder folder, final String subfolder) {
        if (folder == null) {
            return null;
        }
        final List<String> newSubfolders = new ArrayList<>(folder.subfolders);
        newSubfolders.addAll(toFolderNames(subfolder));
        return new Folder(folder.type, folder.uri, folder.persistableFolder, newSubfolders);
    }
Returns a representation of this folder's location fit to show to an end user. This value is volatile if this folder's type is volatile (e.g. {@link FolderType#PERSISTABLE_FOLDER})
main/src/main/java/cgeo/geocaching/storage/Folder.java