This module exportsIn which file is the outgoing thing referenced?

Express does not need to be written like this. Just execute this file directly and add the port to run it.

This is a sample routing file automatically generated by yo's express generator

  var controllers = glob.sync(config.root + '/app/controllers/*.js');
  controllers.forEach(function (controller) {
    require(controller)(app);
  });

Express.js is related to the above picture, which includes all routing files in the controllers folder