The names comes from horology. Complications are the fancy stuff you get on watches... chronometer, date, moon phase. The more there are the more expensive the watch, but for real watches it actually involves top-notch engineering, not flashing a chip.
It's actually not that far off, any high-performance Java app eventuaaly uses the Unsafe class so the developers can do things Java doesn't allow you to, because that's not what it's for. There are people on stackoverflow asking questions about programming problems when writing
JVM bytecode directly... WTF is that all about? These guys probably then consider themselves low level devs. LOL