If identifying the brain region or drug that produces the sensation of identity counts as discovering the essence of identity, does identifying the brain region or drug that produces the illusion of being a cat count as discovering the essence of feline nature? Would the illusion provide us with accurate rules to distinguish felines from other animals?

This is exactly the kind of equivocation that contemporary philosophers complain about nearly every time an arrogant scientist announces the end of philosophy. Not because the scientist's answers are uncomfortable, but because they don't even answer the same question. (Arrogant philosophers, in turn, would say in Latin: ignoratio elenchi.)

Yes, we already know which binaries produce the KDE Plasma Desktop when executed from the bash shell. We also know exactly which bits produce which parts of the GUI. But what we really wanted to know were the conceptual, historical, and perhaps even ethical significance of the design decisions and system architecture that make KDE what it is. (If we replaced Qt with something else, would it still be KDE?) You can't answer that question by showing us a million lines of C++.