/usr/lib/firefox/ is in firefox-locale-or 28.0+build2-0ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/firefox-addons/extensions/
/usr/lib/firefox-addons/extensions/langpack-or@firefox.mozilla.org.xpi
/usr/lib/firefox/distribution/
/usr/lib/firefox/distribution/searchplugins/
/usr/lib/firefox/distribution/searchplugins/locale/
/usr/lib/firefox/distribution/searchplugins/locale/or/
/usr/lib/firefox/distribution/searchplugins/locale/or/amazondotcom.xml
/usr/lib/firefox/distribution/searchplugins/locale/or/bing.xml
/usr/lib/firefox/distribution/searchplugins/locale/or/duckduckgo.xml
/usr/lib/firefox/distribution/searchplugins/locale/or/eBay-in.xml
/usr/lib/firefox/distribution/searchplugins/locale/or/google.xml
/usr/lib/firefox/distribution/searchplugins/locale/or/wikipedia-or.xml
/usr/lib/firefox/distribution/searchplugins/locale/or/yahoo-in.xml