What is the proper location for sshd_config?

I'm running both El Capitan and High Sierra on various boxes. I've been doing a lot of systems setup, backup, copying, etc. and wanted to configure password-less operation of ssh between these machines. I understand the process of setting up password-less ssh operations having done this before (on macOS and non-macOS systems) ... and everything I've done so far is working perfectly fine (as far as I can tell) ... but I don't know why it's working!

All the online (macOS) documentation that I read regarding this process mentions tweaks that should be made to the daemon configuration file: /etc/sshd_config However, that file does not exist! I do have the file /etc/ssh/sshd_config (and a whole lot of other stuff in that directory) but no ssh-related files in /etc.

These online sources say that I need to make the following changes to /etc/sshd_config:

RSAAuthentication yes

PubkeyAuthentication yes

PermitRootLogin no

PasswordAuthentication no

PermitEmptyPasswords no

ChallengeResponseAuthentication no

I've never made a single one of these changes - because there is no /etc/sshd_config in El Capitan or High Sierra - yet everything works as expected. I'm very confused. Can someone enlighten me?

Thanks!