docs: @Override
      protected HashMap<String, byte[]> doBuildZipPass(final BuildData buildData) throws BuildProcessingException {
          final POBuildData poBuildData = (POBuildData) buildData;
  
          // Create the mapping required for the PO files
          if (buildData.getBuildLocale().equals(poBuildData.getPOBuildLocale())) {
              doPOTPopulatePass(poBuildData);
          } else {
              doPOPopulatePass(poBuildData);
          }
  
          // Build the core of the book
          final HashMap<String, byte[]> files = super.doBuildZipPass(buildData);
  
          // Add PO files
          buildPOPass(poBuildData);
  
          return files;
      }