Discover secret message from WordPress, it this user-centered? Or an April fool joke?!

Have you ever use the revision function in WordPress, when I was trying to compare revision but suddenly,

Compare Revision

A secret message appear, it is Danger!?

Danger!01Danger!02Danger!03 Danger!04 Danger!05 Danger!06

Is this part of the April fool matrix joke, and why I have to wait for the message to type out?

Try it yourself, scare your friend, maybe! I don’t think this is user-centered, maybe designer think this is funny, but this can make the user feel bad and helpless.