code: def to_glyphs_master_user_data(self, ufo, master):
      
      target_user_data = master.userData
      for key, value in ufo.lib.items():
          if _user_data_has_no_special_meaning(key):
              target_user_data[key] = value
  
      # Save UFO data files
      if ufo.data.fileNames:
          from glyphsLib.types import BinaryData
  
          ufo_data = {}
          for os_filename in ufo.data.fileNames:
              filename = posixpath.join(*os_filename.split(os.path.sep))
              ufo_data[filename] = BinaryData(ufo.data[os_filename])
          master.userData[UFO_DATA_KEY] = ufo_data
docs: Set the GSFontMaster userData from the UFO master-specific lib data.