Packet Forwarder Default US Channels

I’m having a hard time deciphering what the 8 default uplink channels are from the global_conf.json: https://github.com/OpenChirp/lora_gateway_pf/blob/master/packaging/deb/conf/global_conf.json

Is it 903.9, 904.1(like The Things Network) … or 902.3, 902.5…(starting at channel 0)?

And what are the default downlink frequencies?