Add custom fields to .addCalendar popup

We need to add a field end time and start time to calendar color popup. is it possible to add custom fields in the add calendar popup? right now its just name, description and color… we want to add more fields.

Also if we purchase the license, will we get the unminified javascript of event-calendar.js ??

Unfortunately there are no templates for the popup, so there is no possibility to customize its view.