Quiz: Remember the definition of mal de mer?
Code or designs that trade on a particularly intimate knowledge or experience of a particular operating system or language or complex application interface. Distinguished from deep magic, which trades more on arcane *theoretical* knowledge. Writing device drivers is heavy wizardry; so is interfacing to X (sense 2) without a toolkit. Especially found in source-code comments of the form "Heavy wizardry begins here".
Compare voodoo programming.