In Drupal Fullcalendar, how do I add an additional field to the calendar view?
There's no need to edit any code to add additional field to calendar view.

To add additional field, you need to install Views fields combine or Token module.

How to use Views fields combine:


Edit your calendar view
Add fields you want to display (from field)
Add Combined fields field and select which fields you want to display
Under format -> settings -> customize fields, check Use a custom title checkbox and select the combined fields you created on step 3
Apply changes and save your view then preview the results on the actual page/block.