Alad [1] filed a deletion request for linux-aufs_friendly [2]:
Obscured PKGBUILD, dead upstream patchset, EOL upstream version. Also
maintainer comment:
"For some time now, OverlayFS has been able to do everything I've been
using AUFS for. I'll continue maintaining this, but I won't be using
it myself and suggest that AUFS users take a look at the latest
version of OverlayFS (which can do several branches, too)."
[1] https://aur.archlinux.org/account/Alad/
[2] https://aur.archlinux.org/pkgbase/linux-aufs_friendly/