code: @Override
    public PathImpl schemeWalk(String userPath,
                           Map<String,Object> attributes,
                           String filePath,
                           int offset)
    {
      int p = filePath.indexOf('!', offset);
      String backingPath;
      String jarPath;
  
      if (p > 0) {
        backingPath = filePath.substring(offset, p);
        jarPath = filePath.substring(p + 1);
      }
      else {
        backingPath = filePath.substring(offset);
        jarPath = "";
      }
  
      PathImpl backing = VfsOld.lookup(backingPath);
  
      return JarPath.create(backing).lookup(jarPath);
    }
docs: Lookup the path, handling windows weirdness