Opnsense 23.1 fresh install - no backup config restore
All settings in Unbound - Advanced are empty.
I think this is intentional (so as not to track changes in the unbound pkg) since
https://github.com/opnsense/core/commit/346cc08c9919d1e20aa3869394e27bee45045f2e
https://docs.opnsense.org/manual/unbound.html#advanced (" Some of these settings are enabled and given a default value by Unbound, refer to unbound.conf(5) for the defaults.")