/usr/share/kde4/apps/khelpcenter/plugins/ is in khelpcenter4 4:4.13.0-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/kde4/apps/khelpcenter/plugins/Applications/
/usr/share/kde4/apps/khelpcenter/plugins/Applications/.directory
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/.directory
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man1.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man2.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man3.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man4.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man5.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man6.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man7.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Manpages/man8.desktop
/usr/share/kde4/apps/khelpcenter/plugins/Scrollkeeper/
/usr/share/kde4/apps/khelpcenter/plugins/Scrollkeeper/.directory
/usr/share/kde4/apps/khelpcenter/plugins/Scrollkeeper/scrollkeeper.desktop
/usr/share/kde4/apps/khelpcenter/plugins/fundamentals.desktop
/usr/share/kde4/apps/khelpcenter/plugins/info.desktop
/usr/share/kde4/apps/khelpcenter/plugins/kcontrolmodules.desktop
/usr/share/kde4/apps/khelpcenter/plugins/kicmodules.desktop
/usr/share/kde4/apps/khelpcenter/plugins/kioslaves.desktop
/usr/share/kde4/apps/khelpcenter/plugins/onlinehelp.desktop
/usr/share/kde4/apps/khelpcenter/plugins/plasma.desktop