MarsSeed [1] filed a deletion request for mate-polkit-gtk2 [2]: EOL version from 2016, not compatible with current Mate desktop related packages in Arch repo, and therefore not a drop-in replacement anymore to Arch/extra/mate-polkit.
[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/mate-polkit-gtk2/
