Unity 3D Networking questions (About master servers)

Hello. When I use Unity 3D Networking and make lists to show servers that are up and not port forward and use Hamachi (master server), does that mean that I’m using the Unity 3D Server? Like does the Unity 3D team run it? What is it using when it means master server?
I want to learn what the master server does when I use it on my scripts. How it shows up on my server list. Can you describe it in a easier way to understand? Thanks(future tense)

Yes. It is using the one at Unity HQ by default unless you give it the address of another private master server. You are only supposed to use the default one for testing, not for a finished game.

You can download the Master Server and Facilitator and build and run them on your own computer at home or on a paid VPS host. In theory, at least- I was never able to get my own master server working and instead wrote a set of PHP scripts to do the same thing with an SQL database.