$json = $network->postRequest("download_config_specs", json_encode((object)[]));
$id_lists_lookup = $network->postRequest("get_id_lists", json_encode(['statsigMetadata' => StatsigMetadata::getJson()])); 
Inside the postRequest the code is
    function postRequest(string $endpoint, string $input, array $extra_headers = [], bool $with_status = false)
    {
        $client = new Client([
          'base_uri' => $endpoint === 'dcs' ? DCS_URL : API_URL, 
Which means official IDList::sync and ConfigSpecs::sync calls never use cdn host but regular one.
const API_URL = "https://statsigapi.net/v1/";