Comment # 5 on bug 985937 from Wolfgang Bauer

The openSUSE desktop themes now contain a start.svgz using the openSUSE logo:
https://build.opensuse.org/request/show/405051

So if you choose one of them (openSUSE is the default on a fresh user account
if the openSUSE branding is installed), you'll get the openSUSE logo as icon
for the application launchers.

Will be submitted to Tumbleweed together with the update to Plasma 5.7.0.

As already mentioned, the wallpaper is nothing KDE specific and is not part of
the KDE branding but the general one.
Feel free to file a separate bug about that.
Though I think something like that is better discussed on the mailing lists
(maybe try opensuse-factory as well, as there hasn't been any reply on
opensuse-artwork yet), it is not a bug really.