Thunar launched under Wayland falls back to the default adwaita icon theme when it fails to load vectorized icons.
Steps to reproduce on Sway: $ guix install dconf glib:bin papirus-icon-theme thunar $ gsettings set org.gnome.desktop.interface icon-theme Papirus $ GDK_BACKEND=wayland thunar A workaround to this issue is to prepend 'LD_LIBRARY_PATH=$(guix build gdk-pixbuf+svg)/lib' to the thunar command.