I'd call it a blatantly obvious cultural reference. As if anyone looking at that text won't get it? It isn't like the text is hidden, or anything.
Note that he iconic Easter Egg is *hidden*. The name comes from the idea of the Easter egg hunt. "In computer software, Easter eggs are secret responses that occur in response to an undocumented set of commands. " On DVDs, they typically call for button presses nobody would be expected to make normally. In movies and other media, (say, Disney's "hidden Mickeys"), they are at least subtle, or flash by so quickly (Captain America's shield in arctic ice in the Hulk movie) that nobody'll notice them in standard viewing.
If it is sitting there, in plain text that you're expected to read, it is a geeky cultural reference, not an Easter Egg. Easter Eggs call for some artistry to keep them from being immediately noticed.
