@Override
    public Map<String, Object> listProperties(CompoundName path, Map<String, String> context, Properties substitution) {
        Map<String, Object> map = super.listProperties(path, context, substitution);

        for (Map.Entry<CompoundName, Object> entry : properties.entrySet()) {
            if ( ! entry.getKey().hasPrefix(path)) continue;
            CompoundName propertyName = entry.getKey().rest(path.size());
            if (propertyName.isEmpty()) continue;
            map.put(propertyName.toString(), entry.getValue());
        }
        return map;
    }
Return true if this value should be set in this map, false if the set should be propagated instead
This default implementation always returns true.
container-core/src/main/java/com/yahoo/processing/request/properties/PropertyMap.java