docs: public static List<String> listObjectsInFile(@NonNull File f){
          Preconditions.checkState(f.exists(), "File must exist: %s", f);
  
          List<String> out = new ArrayList<>();
          try (ZipFile zipFile = new ZipFile(f)){
  
              Enumeration<? extends ZipEntry> entries = zipFile.entries();
              while(entries.hasMoreElements()){
                  ZipEntry e = entries.nextElement();
                  String name = e.getName();
                  if(!e.isDirectory() && name.startsWith("objects/")){
                      String s = name.substring(8);
                      out.add(s);
                  }
              }
              return out;
          } catch (IOException e){
              throw new RuntimeException(e);
          }
      }