docs: protected static Set<File> findMapFiles() {
          Set<File> maps = new HashSet<>();
          List<StorageUtils.StorageInfo> storageList = StorageUtils.getStorageList();
          for (int i = 0; i < storageList.size(); i++) {
              File f = new File(storageList.get(i).path + File.separator + "osmdroid" + File.separator);
              if (f.exists()) {
                  maps.addAll(scan(f));
              }
          }
          return maps;
      }