Louis  filed a orphan request for ubuntu-wallpapers :
The maintainer hasn't reacted on out of date fag made back in November '15.
I also sent him an email on in the beginning of April without getting an reaction.
 https://aur.archlinux.org/account/Louis/  https://aur.archlinux.org/pkgbase/ubuntu-wallpapers/
Request #5261 has been accepted by Kyrias :
The user Kyrias disowned the package.