default Map<String, String> extraArchiveMetadata() {
    return Map.of();
  }
Returns {@code true} to set {@code type="overlay"} in {@link Mbtiles} metadata otherwise sets {@code
type="baselayer"}
<p>
The default implementation sets {@code type="baselayer"}

@see <a href="https://github.com/mapbox/mbtiles-spec/blob/master/1.3/spec.md#metadata">MBTiles specification</a>
planetiler-core/src/main/java/com/onthegomap/planetiler/Profile.java