physkets [1] filed a orphan request for netextender [2]: The checksums and some package names haven't been updated in a while, and it doesn't work anymore. The comments detail the specific changes required.
Maintainer had promised changes a month or two ago, but no changes have been made. [1] https://aur.archlinux.org/account/physkets/ [2] https://aur.archlinux.org/pkgbase/netextender/
