Here is exactly what information is collected when you create an account and play on this server.
When you register in-game, your account profile stores your IP address and the email address you typed into the game client. I literally do not have a choice in this; the backend software requires it, and it is automatically stored straight into the server database.
Because it is logged there, this data is visible to me as the server owner. I won't leak anything, nor will I purposefully go looking through the database for your IP addresses. However, it is highly recommended that you just put a dummy email address when registering (like a@gmail.com) and set your ip adress to Rotating. so it changes periodically
If you ever need to perform account actions like changing details, make sure to use the Server Tools panel directly.
If this server's master password ever gets leaked (which is unlikely because of how small this server is), I will manually go into the database and change every single player's IP address and email to 1 and a@gmail.com respectively to stop the hacker from finding out your personal info. After I successfully change the master password back to a safe one, I will manually revert them all.