Reality Composer 3 uses parts of dead game engine?

[Cmaier]

Apple's Reality Composer Pro 3 uses code from a dead game engine

A code leak in a beta for Reality Composer Pro 3 reveals Apple has used elements of a mysteriously cancelled game engine project known as "The Machinery" to make its 3D content tool.

appleinsider.com

Not sure what’s going on here, but it’s interesting.