Just talking to myself over here, I was poking around UE3 Dishonored for some automatic porting to UE5 and I ran into a `StaticMeshCollectionActor` with an array of static mesh components, and nothing else.
After I scratched my head for a while, I realized that it contains serialized transformation matrices for said static meshes, referenced by package index. So I was able to extract the data and convert the matrices into locations/rotation/scale and automatically populate some bits and pieces of a Dishonored map into unreal engine 5.
Nothing really to show as a complete map, just take my word for it, I was just taken aback by how unreal engine 3 used to handle static mesh actors when cooked for consoles

UE4 to UE5 porting is more straightforward.