World Partition is Unreal Engine 5's system for large worlds. Instead of you carving a level into sublevels by hand and managing what loads when, the world is divided into a spatial grid and streams by distance automatically.
The team consequence is larger than the technical one. Before World Partition, collaborating on a big level meant sublevels assigned to individuals, and the boundaries were drawn around team structure rather than around the game. World Partition removes that, and because it enables One File Per Actor by default, actors live in separate files and two people can genuinely work in the same world at the same time.
Data layers complement the grid by grouping actors logically rather than spatially: a lighting pass, a gameplay pass, seasonal variants of the same district. They map neatly onto how a team divides work, and let people load only what they need.
For source control, the shape of your project changes. The .umap shrinks to a configuration shell, a `__ExternalActors__` tree appears holding thousands of small binaries, and HLOD output shows up as derived data you must decide whether to version. What survives from before is that the level file, individual actors, and shared assets are all still binary and still need locking.