I have a feeling that this is more than just a slightly amusing easter egg in the Citymapper iOS 9 update and instead is an interesting experiment with the Spotlight recommendations algorithm.
Apple have said they'll recommend your app to people who don't have it installed when they use Spotlight search. They're monitoring the apps and keywords that people with your app installed interact with and recommending apps from there. My hunch is that this is an experiment to see what kind of traffic through a term it takes to start getting recommended. Of course, Apple will probably remove it from the index for these terms manually once they spot it but of course Citymapper will have the data by that point. 😀 (If you're reading this, I really hope my linking to it doesn't spoil your experiment!)
If it's not an experiment, and just an easter egg. I hope you have analytics on it so it's not too late to grab this data. Please then write about it!
I know the And Finally is supposed to be a short and sweet one but I wanted to write this and it didn't fit anywhere else. 😎