I'm going to take a stab at this one. We already know that the Bunker Apple Yellow Sky […+1] translates to CBZT, which turned out to be the registration # of a helicopter. Don't have confirmation that it was THE helicopter, but seems to fit. We know that those words mean more than just the first letters. If they had wanted the letters only (+1) it would have been military alphabet: Bravo Alfa Yankee Sierra
Since this event has already passed, this stringer gives us more chance to align the stringers with the known event. Why Bunker? Does a bunker exist on Waddeson Estate that is not public but known to Intel? Was the mission to locate a bunker? Are there apple orchards, or even an apple tree to help locate the bunker? Yellow could be caution, but it could also be an identifier of gold. It is the usual case with gold to minimize its importance as is done with our reserves at the Treasury. They dont audit it in order to downplay its importance in the public mind.
Sky could mean the helicopter would come from the sky, but isnt that rather redundant? Why mention it when the helicopter registration # is already included? What new info does it add? don't helicopters pretty much always come from the sky? So I would look for another meaning of sky. Sky could instead mean that the location of the bunker and the content had been seen from the skyor could be seen from the sky. Q later says these words are a guide to "reading the map". How could they not be looking for a bunker then?