Please see the below diagram from Wikipedia explaining the difference between Mach and Darwin. I agree with OP that Fuschia is much closer to Darwin than Mach.

Please see the below diagram from Wikipedia explaining the difference between Mach and Darwin. I agree with OP that Fuschia is much closer to Darwin than Mach. https://en.m.wikipedia.org/wiki/File:Diagram_of_Mac_OS_X_architecture.svg https://en.m.wikipedia.org/wiki/File:Diagram_of_Mac_OS_X_arc...