Youtube video linked of a guy performing the Karanas 'easter egg' warp on early p99 blue. I don't know if it was classic because I wasn't in the know at the time, but I would guess it was.
Seems not implemented on green.
https://www.youtube.com/watch?v=IrsXcNez8Gw
Also note the comment about a warp in butcherblock. Not sure about that one.