So I was looking through the sources of nano and I seemed to have discovered a previously-unknown (at least based on a quick search) easter egg.

First modify the buffer somehow. It really doesn't matter if you just type in "test"

Hit ^X to exit nano. When it asks you if you want to save the buffer hit Y

Save the file as "zzy" and press ENTER to trigger the Easter egg

^X+Y+zzy is likely a reference to xyzzy, a cheat code originally used in Colossal Cave Adventure[1]

1: https://en.wikipedia.org/wiki/Xyzzy_%28computing%29?wprov=sf...