Individual vendors are allowed (and even encouraged) to expand on the basic function library with additional functions of their own.

各家供应商都获得允许(甚至被鼓励)使用自己的额外函数对基本函数库进行扩展。

youdao

Creative are touting the Zen as a far more powerful player than Apple's offering, with additional functions such as FM radio and a built-in mic.

BBC: Creative Zen Vision: M

The iTech system integrates the normal functions of a gauge cluster with additional functionality, like navigation commands, climate controls and audio functions.

FORBES: 2011 Jaguar XJL Test Drive and Review