The generator was created by Aulden Carter and can be downloaded via Unreal Engine Marketplace.
According to the creator, the buildings are generated from the ground up during each cycle based on the properties given. Thanks to the seed-based approach, the exact generation can be regenerated given the same seed and properties. Building length, width, and height can be determined prior to generation. The list of properties includes roof, cornice, curb, gutter, entrances, signs, etc.
What's more, the generator supports UE5's Lumen and Nanite and can be expanded by adding Quixel content via Quixel Bridge into the generator. The buildings are game-ready in terms of draw calls as they utilize Unreal's HISM, which also supports LODs.
You can learn more and purchase the generator for $39.99 by visiting its UE Marketplace page.