Access URL field in a calendarEvent

I’m new here and want to write a scriptable which cleans up my calendar entries.
The entries are synced from my companies Secure Hub (by Citrix).

Unfortunately there is an error in the sync process witch duplicates entries. This causing one event apearing mutible times in the calendar.

The wrong calendarEvents can be identified by the broken url in the URL field. But this field is not visible for me.

How can I access the URL field of a calendarEvent?

Kind regards,