NSD has the ability to automatically generate a zone's filename based on a template string, instead of requiring them to be specified within each zone's configuration:

              %s is replaced with the zone name.

              %1 is replaced with the first character of the zone name.

              %2 is replaced with the second character of the zone name.

              %3 is replaced with the third character of the zone name.

              %z is replaced with the toplevel domain name of the zone.

              %y is replaced with the next label under the toplevel domain.

              %x  is  replaced  with  the  next-next  label under the toplevel
              domain.

It would be useful if BIND has a similar feature. This would also work well with Catalog Zones, where it is not expected that the Catalog Zone itself would hold the filename, but where the secondary server would synthesise a filename for itself.