non-basic; outside the basics
Computing term used to describe features, settings, or operations that are not part of the basic or default set. Often contrasted with 基本 (basic).
このソフトの基本外の機能はマニュアルを参照してください。
For the non-basic functions of this software, please refer to the manual.
Compound of 基本 (basic) + 外 (outside). The exact derivation is uncertain, but it likely arose in technical contexts to categorize non-basic elements.