/usr/share/kde4/apps/kwin/decorations/ is in kde-window-manager-common 4:4.11.8-0ubuntu6.
This file is owned by root:root, with mode 0o755.
..
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/contents/
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/contents/config/
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/contents/config/main.xml
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/contents/ui/
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/contents/ui/PlastikButton.qml
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/contents/ui/config.ui
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/contents/ui/main.qml
/usr/share/kde4/apps/kwin/decorations/kwin4_decoration_qml_plastik/metadata.desktop