Why domains on a Plesk server automatically have aliases for cpcalendar and cpcontacts?

Question

Why domains on a Plesk server automatically have aliases for cpcalendar and cpcontacts?

Answer

These alias domains (cpcontacts and cpcalendars) are usually created during a migration process from cPanel. 

If any necessary data has been backed up from these directories, and it can be confirmed that the calendar and contact data are not in use or required by any applications or users, then these aliases may be removed.