Not everything made by KDE uses C++. This is probably obvious to some people, but it’s worth mentioning nevertheless.
And I don’t mean this as just “well duh, KDE uses QtQuick which is written with C++ and QML”. I also don’t mean this as “well duh, Qt has a lot of bindings to other languages”. I mean explicitly “KDE has tools written primarily in certain languages and specialized formats”.
↫ Thiago Sueto
If you ever wanted to contribute to KDE but weren’t sure if your preferred programming language or tools were relevant, this is a great blog post detailing how you can contribute if you are familiar with any of the following: Python, Ruby, Perl, Containerfile/Docker/Podman, HTML/SCSS/JavaScript, Web Assembly, Flatpak/Snap, CMake, Java, and Rust. A complex, large project like KDE needs people with a wide variety of skills, so it’s definitely not just C++.
An excellent place to start.