@NonNull
    public FolderType getBaseType() {
        if (persistableFolder != null) {
            return persistableFolder.getFolder().getBaseType();
        }
        return getType();
    }
The current base type, which is always an immutable type (e.g. may never be {@link FolderType#PERSISTABLE_FOLDER}). Return value is volatile
main/src/main/java/cgeo/geocaching/storage/Folder.java