The nearest city to the site of the War Tavern, as of the most recent complete rearrangement of all Carrotian landmarks, was a (rather blue) place named - unoriginally enough - "Bunnyburrow".
Bunnyburrow was known for being primarily a burrow - that is, instead of the more common normal city, a series of underground tunnels and caverns - only with more advanced technology then you find in most holes in the ground. There were rumors Bunnyburrow had originally been a secret turtle base, only the rabbits had taken it, but this was widely disregarded as demeaning rabbitarian intelligence.
As is often the way with old places with lots of technology, few really remembered how much of the various machines houses in Bunnyburrow worked, fewer cared to tell anyone else, and even less hung around long enough to listen. It was not really widely regarded at all, which was strange, as it had the potential to become quite a popular place, but the rabbits living inside it enjoyed quite an easy life, what with the automatic food processors, machines which always produced a strange liquid that was almost (but not quite) completely unlike tea, and a strange economic system which had totally abolished the use of money.
If you have not already guessed as much, it was Bunnyburrow Firefox brought Jack to, though it was unlikely he had it - or any paticular city - in mind beforehand. Bunnyburrow was often known to redirect nearby travellers towards it.
If you had guessed as much, this is still what happened.