As part of the devs farewell message on their site, they have included malicious code to make each visitor sends 2,000 requests to the dbzer0 servers in an attempt to DDOS and take the instance offline.
Don't have to install anything. Some instance make it the default though, but I think most front end like Voyager or Alexandrite (or tesseract since we are discussing it) you can visit their web page and point your home instance to use their UI.
Edit; I'm copying a comment someone else made here https://piefed.zip/comment/6322459 since it's pretty consise than what I explained 😅
It's a frontend. So literally a skin to make a website look prettier and more organized.
Imagine a waiter starts telling customers what foods they are allowed to eat. He wasn't the chef, the manager, the owner, anybody.
That's how stupid it was.