It’s node-based tool with which you scatter point instances in the world and read them back at runtime to lazily instantiate prefabs. This means prefab instances are only created when requested and dynamically enabled/disabled when needed, based on the player distance.
You preview point instances as optimized cylinders or spheres and scatter them on a Unity Terrain using rules and filters like world height, slope angle, distance between points, terrain layers and more. The points are grouped in categories by creating Scatter Layers, which are scriptable objects defined by a prefab palette and weight for each, represented by a distinctive color (e.g green for the big trees, blue for the medium ones in the example video; the smaller vegetation is using terrain details but it would work the same way, just with increased density).
The main goal was to replicate something like Houdini's HeightField Scatter node and related filters without the need of external tools and avoid having thousands of gameobjects in the editor which makes working in it practically impossible.
Is there something similar for Unity I don’t know of apart from assets like MicroVerse which let procedurally place objects with rules but with the downside of having thousands of gameobjects which slow down every in editor operation? I mainly made it for me because I couldn’t find a valid alternative.