code: def _has_extras(ctx):
      
      if not ctx.index.entries:
          return False
  
      return ctx.data_offset > 8 and ctx.data_offset > (ctx.signatures.offset_end + 8)
docs: Determine if a MAR file has an additional section block or not.
  
      It does this by looking at where file data starts in the file. If this
      starts immediately after the signature data, then no additional sections are present.
  
      Args:
          ctx (context): construct parsing context
  
      Returns:
          True if the MAR file has an additional section block
          False otherwise