KDE is not only a desktop environment but also a software ecosystem, providing not only software for regular desktop use, but also tools to create such software. Whether developing for KDE or programming in general or doing even web development, KDE offers programs that can help make any programmer's, or even non-programmer's, life easier and more productive.
An advanced text editor with many features including syntax highlighting
Manage the files that make up your project
Web development with PHP
See clearly the differences between two versions of a text file