Welcome to Witness - an open-source fictional world. This world is different from other fictional worlds, in that it pays a lot of attention to its economies, and makes its economies radically different from the one we live in. The culture of the Witness has passed through several stages and varies between its distrikts.
Witness is the most populous seasteading megacity on record. Initially developed under Project Viking (which gave birth to other noted cities such as Byzantium and Vivarium), Witness grew far beyond its original physical and legal bounds, and today is considered the cultural, financial and media capital of the post-Sundering world. Doubly so since it both anchors itself to semi-stable landmasses and produces new ones of its own: it is therefore a navigational landmark in this post-climate-change reality.
Whereas most other Project Viking cities operate as a single territory overseen by a single government and State Machine, Witness operates as a collection of interdependent Distrikts that function de facto as city-states in their own right. Each city-state is an implementation of a particular set of economic, philosophical and moral social contracts, although some aethnographers have pointed out the phenomenon of boundary bleed (which is almost unseen in other cities).
Between the Distrikts runs the Migrant Train, a zero-cost solution for citizens who wish to live under a different social contract. While the State Machine of Witness is de jure overseer of all territories, in reality it manages only portions of infrastructure, guides multi-distrikt disaster response, and policing in instances where inter-Distrikt conflict seems imminent.