improved debian/$foo and make it lintian clean.

debian/lxqt-system-theme.install

@@ -0,0 +1,4 @@
+usr/share/lxqt/themes/system
+usr/share/lxqt/graphics/
+usr/share/icons/hicolor/
+

debian/lxqt-themes.install

@@ -0,0 +1,5 @@
+usr/share/lxqt/themes/ambiance
+usr/share/lxqt/themes/dark
+usr/share/lxqt/themes/frost
+usr/share/lxqt/themes/kde-plasma
+usr/share/lxqt/themes/light

debian/rules

@@ -5,3 +5,6 @@ export DEB_LDFLAGS_MAINT_APPEND = -Wl,--as-needed
 
 %:
 	dh ${@} --buildsystem cmake
+
+override_dh_missing:
+	dh_missing --fail-missing

debian/source/format

@@ -1 +1 @@
-1.0
+3.0 (quilt)