Install GTK+4 theme

Packages describing “gtk4” as local USE flag

Package “gtk4” Flag Description
x11-themes/arc-theme Install GTK+4 theme
games-strategy/freeciv Build the gtk4 client
app-i18n/ibus Enable the GTK-4 input method module
net-vpn/networkmanager-sstp Use gui-libs/gtk for GUI support.
net-vpn/networkmanager-strongswan Use GTK4 instead of GTK3.
www-client/chromium Build with GTK4 headers.

All packages providing a “gtk4” USE flag (4)