The code for this website is located at https://websvn.kde.org/trunk/www/sites/www/ and can be cloned with
svn co svn://anonsvn.kde.org/home/kde/trunk/www/sites/www kde-org
Some instructions to get a local working version of kde.org can be found at: https://community.kde.org/KDE.org/Local_Setup, in case of problem with the installation please ping 'Carl Schwan' in #kde-www in Matrix/IRC.
You can find the source SASS for the website in https://invent.kde.org/websites/aether-sass