It could be good t have an Export (or Backup) button, to be able to save existing subscritions. At the moment, we can’t even select subscriptions address to be able to save them to a file. In case it is a shared calendar, we have to ask ics address again.
@armadillo Synchronizing events (and tasks) is a very complicated task and it’s not done with simple copy operations. All the complex operations and requirements are best covered by a separate protocol – as CalDAV.