The nx---- plugins are not official, but are built to Ahead's SDK
(last compilation date, 1st April - so maybe they needed recompiling, to support a supposedly static API?).
I hope the chap does one to link to command line encoders with parameters, as that would allow a wide choice - just compare "Exact Audio Copy" - which can work with almost any codec you can source - with Ahead's self-serving plugin approach - they eventually bowed to criticism by opening it up, but that's too little, too late!