/usr/share/kde4/apps/khtml/kpartplugins/ is in konq-plugins 4:15.12.3-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/kde4/apps/khtml/kpartplugins/akregator_konqfeedicon.desktop
/usr/share/kde4/apps/khtml/kpartplugins/akregator_konqfeedicon.rc
/usr/share/kde4/apps/khtml/kpartplugins/autorefresh.desktop
/usr/share/kde4/apps/khtml/kpartplugins/autorefresh.rc
/usr/share/kde4/apps/khtml/kpartplugins/khtmlsettingsplugin.desktop
/usr/share/kde4/apps/khtml/kpartplugins/khtmlsettingsplugin.rc
/usr/share/kde4/apps/khtml/kpartplugins/minitoolsplugin.desktop
/usr/share/kde4/apps/khtml/kpartplugins/minitoolsplugin.rc
/usr/share/kde4/apps/khtml/kpartplugins/plugin_adblock.desktop
/usr/share/kde4/apps/khtml/kpartplugins/plugin_adblock.rc
/usr/share/kde4/apps/khtml/kpartplugins/plugin_babelfish.rc
/usr/share/kde4/apps/khtml/kpartplugins/plugin_domtreeviewer.desktop
/usr/share/kde4/apps/khtml/kpartplugins/plugin_domtreeviewer.rc
/usr/share/kde4/apps/khtml/kpartplugins/plugin_rellinks.desktop
/usr/share/kde4/apps/khtml/kpartplugins/plugin_rellinks.rc
/usr/share/kde4/apps/khtml/kpartplugins/plugin_translator.desktop
/usr/share/kde4/apps/khtml/kpartplugins/plugin_validators.desktop
/usr/share/kde4/apps/khtml/kpartplugins/plugin_validators.rc
/usr/share/kde4/apps/khtml/kpartplugins/plugin_webarchiver.desktop
/usr/share/kde4/apps/khtml/kpartplugins/plugin_webarchiver.rc
/usr/share/kde4/apps/khtml/kpartplugins/uachangerplugin.desktop
/usr/share/kde4/apps/khtml/kpartplugins/uachangerplugin.rc