xantares [1] filed a deletion request for mingw-w64-qwt-qt6 [2]: to mimic the switch in the default repos,
mingw-w64-qwt is now the qt6 variant and mingw-w64-qwt-qt5 is the qt5 variant [1] https://aur.archlinux.org/account/xantares/ [2] https://aur.archlinux.org/pkgbase/mingw-w64-qwt-qt6/
