Shortly after release of the update, I went to check the hidden tunnel under the map as per my usual routine, and stumbled across this object in the room with the vent that leads to the tunnel, found in one of the subway tunnels.
Both of those doors have been there for a long time. I was checking out the tunnel first for changes and happened to see a change in the normally-accessible area with the vent.
While it appears there are two ājokeā numbers on it (420 and 69) this may be just to throw people off as the numbers may not even go in that sequence, if there even is a sequence.
Havent figured out the numbers but I went OOB and the cone is pointing to the empty patio-thing at the back of the tower. Where the landscaping Project 23 sign is.