This is the Web2 problem
The challenge simply states "Find the key!" and it gives us the challenge URL.
The first thing I usually do with a web challenge is to run dirbuster, spider the target and check the it with Nmap.
Checking with Nmap didn't result in anything interesting. However dirbuster did. I found two interesting folders.
The first one is "SecretAdminPanel" and the second one was "logs"
I visited "SecretAdminPanel" and I saw this.