GTK2 and GTK3 Configurator for KDE.

Configuration dialog to adapt GTK applications appearance to your taste under
KDE. Among its many features, it lets you:
* Choose which theme is used for GTK2 and GTK3 applications.
* Tweak some GTK applications behaviour.
* Select what icon theme to use in GTK applications.
* Select GTK applications default fonts.
* Easily browse and install new GTK2 and GTK3 themes.

WWW: https://www.kde.org/plasma-desktop