You are developing open-source software based on existing source code developed by someone else. what is the term for the piece of software you develop?

Derivative work

Explanation:

The idea of derivative work does not belong to the field of computing originally, it is a concept in copyright law referring to written works, art works, music etc. In applying this to computing, it is not generally agreeable what constitutes a derived work (a piece of software), but it is reasonable to understand that if you build a software using another person's codebase, or when a reasonable part of your code is taken from someone's code, then your software is not entirely yours because it is derived from others and a permission known as copyleft is required.

answer; wage income;