The FreeBSD packages of KDE software -- the KDE 4 desktop, and soon KDE Frameworks 5 and Plasma 5 Desktop and KDE Applications -- have traditionally been shipped pretty much as delivered from the upstream source. We compile, we package, and there is very little customization we do as a "distro". The KDE 4 packages came with a default wallpaper that was a smidgen different from the one shipped with several Linux distro's. I think Ivan Cukic did that artwork originally. For Plasma 5 Desktop, we also wanted to do a tiny bit of branding -- just the default wallpaper for new users, mind.
Thanks to the tremendously helpful Plasma crew who answered my questions about setting a default wallpaper by producing the necessary files on the spot. After a tiny amount of massaging, I've now got a package that does the FreeBSD branding of the Plasma 5 Desktop for us. Of course we retain the upstream settings and wallpapers too.
Also great thanks to Timothee Giet, for producing the image (based on his Flying Konqui) that we're now going to use as the default wallpaper -- Konqui flying on BSD, that's just what we want, after all.