void09 [1] filed a deletion request for xfce4-taskbar-plugin [2]:
"Since the 4.4 version of the Xfce, the taskbar plugin is shipped with the panel. So there is no need to install any other stuff."
Also the source url is gone.
[1] https://aur.archlinux.org/account/void09/ [2] https://aur.archlinux.org/pkgbase/xfce4-taskbar-plugin/
Request #12952 has been rejected by Alad [1]:
This version of xfce4-taskbar-plugin was created in 2011. Xfce 4.4 is from 2007.
aur-requests@lists.archlinux.org