The NewMouse program is a driver for serial mice. It cannot be used with PS/2 devices.
But it also invented a set of rawkey codes used to feed wheel movements into input.device. These codes are called "the NewMouse standard". The codes, not the program.
Programs supporting the NewMouse standard rely on the rawkey codes, not on the NewMouse program. Most drivers for PS/2 mice (e.g. Cocolino, Topolino, EZMouse etc.) feed exactly the same rawkey codes into input.device for wheel movements. This way programs supporting NewMouse automatically support Cocolino etc., too.
Bye,
Thomas