private static Set<ConfigKey<?>> withParentConfigId(Collection<ConfigKey<?>> keys) {
            Set<ConfigKey<?>> ret = new LinkedHashSet<>();
            for (ConfigKey<?> k : keys) {
                ret.add(new ConfigKey<>(k.getName(), parentConfigId(k.getConfigId()), k.getNamespace()));
            }
            return ret;
        }
The listing URL for this config in this service

@param key config key
@param rec recursive
@return url
configserver/src/main/java/com/yahoo/vespa/config/server/http/v2/HttpListConfigsHandler.java