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”.
Note that I said “specialized formats”.