/usr/lib/ is in firefox-locale-hr 11.0+build1-0ubuntu4.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/firefox-addons/
/usr/lib/firefox-addons/extensions/
/usr/lib/firefox-addons/extensions/langpack-hr@firefox.mozilla.org.xpi
/usr/lib/firefox/
/usr/lib/firefox/distribution/
/usr/lib/firefox/distribution/searchplugins/
/usr/lib/firefox/distribution/searchplugins/locale/
/usr/lib/firefox/distribution/searchplugins/locale/hr/
/usr/lib/firefox/distribution/searchplugins/locale/hr/amazon-en-GB.xml
/usr/lib/firefox/distribution/searchplugins/locale/hr/bing.xml
/usr/lib/firefox/distribution/searchplugins/locale/hr/eBay-en-GB.xml
/usr/lib/firefox/distribution/searchplugins/locale/hr/eudict.xml
/usr/lib/firefox/distribution/searchplugins/locale/hr/google.xml
/usr/lib/firefox/distribution/searchplugins/locale/hr/twitter.xml
/usr/lib/firefox/distribution/searchplugins/locale/hr/wikipedia-hr.xml
/usr/lib/firefox/distribution/searchplugins/locale/hr/yahoo.xml