/usr/ is in firefox-locale-xh 28.0+build2-0ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/firefox/
/usr/lib/firefox/distribution/
/usr/lib/firefox/distribution/searchplugins/
/usr/lib/firefox/distribution/searchplugins/locale/
/usr/lib/firefox/distribution/searchplugins/locale/xh/
/usr/lib/firefox/distribution/searchplugins/locale/xh/google.xml
/usr/lib/firefox/distribution/searchplugins/locale/xh/duckduckgo.xml
/usr/lib/firefox/distribution/searchplugins/locale/xh/wikipedia.xml
/usr/lib/firefox/distribution/searchplugins/locale/xh/bing.xml
/usr/lib/firefox-addons/
/usr/lib/firefox-addons/extensions/
/usr/lib/firefox-addons/extensions/langpack-xh@firefox.mozilla.org.xpi
/usr/share/
/usr/share/doc/
/usr/share/doc/firefox-locale-xh/
/usr/share/doc/firefox-locale-xh/copyright
/usr/share/doc/firefox-locale-xh/changelog.Debian.gz