http://natas3.natas.labs.overthewire.org
Username: natas3
Password: (natas3_password)

The clue says that not even Google will find it this time.

After a bit of digging, we found out what the robots.txt file is used for.

We then tried accessing it via the browser.

We discovered a directory named /s3cr3t/.

So, we navigated to it through the browser.

There, we noticed a file called users.txt

Once we opened it, we found our flag.

Fantastic! This flag is your key to the next challenge.