code: function configMissingError(configName) {
      const error = new Error(`Failed to load config "${configName}" to extend from.`);
  
      error.messageTemplate = "extend-config-missing";
      error.messageData = {
          configName
      };
      return error;
  }
docs: Creates an error to notify about a missing config to extend from.
  @param {string} configName The name of the missing config.
  @returns {Error} The error object to throw
  @private