If, like me, you occasionally revel in a good old "people talking straight past each other" e-mail fight, read this one, linked from the wiki page, in which "80n" claims to know of trap streets in OSM.
https://lists.openstreetmap.org/pipermail/legal-talk/2008-Fe...
It’s probably not an Easter egg, but for my neighborhood in Yokohama, Japan, some maps—Mapion, Google, Apple—show a nonexistent street next to my house while others—Yahoo, OSM—don’t:
https://gally.net/temp/20240214maps/index.html
The nonexistent street has been appearing on maps for at least a quarter century.
The links to apple copying OSM are pretty interesting in their own right, and demonstrate why OSM's policy is to not include traps in their maps. It's already pretty obvious when they are copied from. TL;DR OSM maps are far more detailed, in places, than the average map so you'll end up copying features you aren't trying to map as something else.
Seems all the links to google maps easter eggs are 10-20 years old and fixed.
Known also as a trap street [0], a name which I believe is more widely used?
[0] https://en.wikipedia.org/wiki/Trap_street