Made a comment up above, but that's tdpServer and tmpServer (sometimes tdpd and tmpd) and it's what I use in my python implementation of tmpcli, the (somewhat broken) client binary on some TP-Link devices.

You're correct, it gives you access to everything the Tether app can do.

https://github.com/ropbear/tmpcli

I had been trying to find that again! It was instrumental in some RE/VR I did last year on tmp and the differences between the UDP socket (available without auth) and the TCP socket. Thanks for making that.

I can't remember the details of the scheme, but it also allows you to authenticate using your TPLink cloud credential. If my memory is correct, the username is md5(tplink_account_email) and the password is the cloud account password. If you care, I can find my notes on that to confirm.