This surely isn't what was meant in previous conversation, but Unreal Engine 5 added MassEntity which is uh... an Entity Fragment Processor approach. (Because Components are already an object that exists, it probably would have been an extra special kind of confusing if it adopted typical ECS naming.)

https://docs.unrealengine.com/5.0/en-US/overview-of-mass-ent...

Based on the definitions in this thread, it wouldn't be a stretch to pair Unreal's `AActor` as the entities and `UActorComponent` as the components. You could technically go a step further and pair `UWorldSubsystem` as the system.

I realize that there's the whole "grouping" and "batching" concept in ECS paradigms, but I'm failing to see how that's much different from using the functions in `UWorld` that can query both components and actors of a certain class.