There is no "local" sync. There is only caldav for calendars and as for tasks, I am only aware of the provider for google calendar that even tries to sync tasks to a remote server. What happens when V114 or 115 is released in a May/June 2023 time frame is still a little unclear to me. It does have a sync like Firefox, but exactly what is synced and how it is propagated is still something of a black hole, except to the developer doing the work perhaps. My copy of daily (the daily developer build) has a menu entry that links to the Mozilla development sync server but as I have heard nothing asking for testing, I am assuming it is still unstable, even in the development environment.