/usr/share/roundcube/plugins/quickrules/localization/ is in roundcube-plugins-extra 0.6-20111030.
This file is owned by root:root, with mode 0o755.
..
/usr/share/roundcube/plugins/quickrules/localization/cs_CZ.inc
/usr/share/roundcube/plugins/quickrules/localization/de_CH.inc
/usr/share/roundcube/plugins/quickrules/localization/de_DE.inc
/usr/share/roundcube/plugins/quickrules/localization/en_GB.inc
/usr/share/roundcube/plugins/quickrules/localization/en_US.inc
/usr/share/roundcube/plugins/quickrules/localization/hu_HU.inc
/usr/share/roundcube/plugins/quickrules/localization/it_IT.inc
/usr/share/roundcube/plugins/quickrules/localization/pl_PL.inc
/usr/share/roundcube/plugins/quickrules/localization/pt_BR.inc
/usr/share/roundcube/plugins/quickrules/localization/pt_PT.inc