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kvantum-qt5 only ever existed to dark-mode VLC, and VLC is retired.
qt5-wayland was the Qt5 Wayland platform plugin, but it also quietly
dragged in qt5-declarative, which is what kept sddm's Qt5 greeter alive.
No application we ship runs on Qt5 any more, so the whole stack goes
from fresh installs: about 110 MiB across kvantum-qt5, qt5-wayland,
qt5-declarative, qt5-base, qt5-svg, qt5-x11extras and qt5-translations.
fcitx5-qt keeps a few Qt5 objects it builds regardless, and they simply
go unused.

sddm picks its greeter from the theme's SddmGreeterTheme/QtVersion and
defaults that key to 5, so a theme without it execs the Qt5
/usr/bin/sddm-greeter. That tie is only an optdepend, so pacman would
happily take qt5-declarative and leave a login screen that cannot start.
The theme declares QtVersion=6 now, and the Qt6 greeter renders it
unchanged.

kvantum, the Qt6 style engine behind QT_STYLE_OVERRIDE, was only ever
present as a dependency of kvantum-qt5, so the package list swaps to it
rather than dropping the line. obs, kdenlive and the share picker keep
the styling they have today.

Machines already installed keep their Qt5 stack. Shedding it there means
deciding which greeter sddm will actually launch, and that means
reimplementing its config loader: sddm reads every file in sddm.conf.d
whatever its extension, QSettings trims keys and lets the last duplicate
win, and ThemeDir can move the themes entirely. Not worth risking a
login screen for 110 MiB that a reinstall reclaims anyway.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

2026-07-29 14:13:16 -04:00