It has css class and style, it will match the color-scheme. If someone wants to test it before the update, open up terminal and run:
wget https://gitlab.manjaro.org/artwork/themes/breath2/-/raw/master/plasma/breath2/icons/manjaro.svgz
sudo cp manjaro.svgz /usr/share/plasma/desktoptheme/breath2/icons/manjaro.svgz
overwrite it and then log out and back in.