Yep not even a random display in JS. I looked at the source code of the webpage.
There is nothing curious. Custom JS is here: https://verdagon.dev/components/annotated.js and does only trivial things. Not a real easter egg for the client part. Maybe the easter egg is in server part that sends the HTML with or without it depending on hour or something. No need to waste more time on it, there is no funny code behind :)