There is only one file type that uses the .VCS extension:
vCalendar Event File
Contains information about an event or appointment, which can be imported into a calender or scheduling program; saved in the vCalendar "Electronic Calendaring and Scheduling Exchange" format; includes the event date and time and other information about the event.
VCS files can be imported and exported by several programs, including Microsoft Outlook and Apple Calendar. They are also supported by various PDA software programs, such as Palm Desktop.
NOTE: Apple Calendar was formerly known as Apple iCal but was changed in 2012 with the release of OS X Mountain Lion.
Updated: May 2, 2015