php framework

A framework is a basic conceptual structure used to solve or deal with complex problems. This broad definition is very popular, especially in software concepts.
Secondary development, simply put, is to customize and modify existing software, expand functions, and then achieve the functions you want. Generally speaking, the kernel of the original system will not be changed.

In this sense, it is not secondary development
because tp, ci, zf, yii.... just provide a solution, not a complete software in itself