artfox3 [1] filed a deletion request for applet-window-buttons-git [2]: Broken, cannot be built on current Arch / KDE Plasma 6. Also upstream abandoned for 2 years. Please delete this as it seems not useful to keep (also does not follow ArchWiki's KDE package naming). @arojas has published a custom-patched build to Arch repo that works with current Plasma version: https://archlinux.org/packages/?q=plasma-applet- window-buttons
[1] https://aur.archlinux.org/account/artfox3/ [2] https://aur.archlinux.org/pkgbase/applet-window-buttons-git/
