I dont think this is supported yet. You can read below the "Add by URL" that this is for iCals.
With respect to DalmTo's suggestion, I tried placing an iCal URL as "id" in the POST request in
CalendarList.insert. It didn't work.
I got an error saying:
"code": 404,
"message": "Not Found"
But, when I added it manually using the Add by URL field, it was inserted.
This only means that CalendarList.insert
doesn't accept iCal URLs. I also checked the CalendarList resource and no mention of iCal URLs were present.