Package: bind9 Version: 1:9.16.4-1 Current versions of BIND provide a hardcoded list of root servers which provide access to the root zone via AXFR so that they can be used as primaries in a "mirror"-type root zone (https://gitlab.isc.org/isc-projects/bind9/-/blob/main/bin/named/config.c#L305).
It seems that list should likely be moved to dns-root-data so that it can be updated separately from a full bind installation (and possibly used by other resolvers). I presume such a file should be usable as an include statement in bind.conf, though this may preclude use by other resolvers. Feel free to move this to dns-root-data or tell me off to go file upstream or so if this isn't the right place to file.