code: static String8 createZipSourceNameLocked(final String8 zipFileName,
        final String8 dirName, final String8 fileName) {
      String8 sourceName = new String8("zip:");
      sourceName.append(zipFileName.string());
      sourceName.append(":");
      if (dirName.length() > 0) {
        sourceName.appendPath(dirName.string());
      }
      sourceName.appendPath(fileName.string());
      return sourceName;
    }
docs: /*
  Create a "source name" for a file from a Zip archive.