/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/ is in plasma-widgets-active 2.0+git2012021101-0ubuntu4~ppa3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/code/
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/code/LayoutManager.js
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/config/
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/config/main.xml
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/ui/
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/ui/PlasmoidContainer.qml
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/ui/SlidingPanel.qml
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/ui/TaskWidget.qml
/usr/share/kde4/apps/plasma/plasmoids/org.kde.active.systemtray/contents/ui/main.qml