/usr/ is in firefox-launchpad-plugin 0.4.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/firefox-addons/
/usr/lib/firefox-addons/searchplugins/
/usr/lib/firefox-addons/searchplugins/launchpad-bug-lookup.xml
/usr/lib/firefox-addons/searchplugins/launchpad-bugs.xml
/usr/lib/firefox-addons/searchplugins/launchpad-package-bugs.xml
/usr/lib/firefox-addons/searchplugins/launchpad-packages.xml
/usr/lib/firefox-addons/searchplugins/launchpad-people.xml
/usr/lib/firefox-addons/searchplugins/launchpad-specs.xml
/usr/lib/firefox-addons/searchplugins/launchpad-support.xml
/usr/share/
/usr/share/doc/
/usr/share/doc/firefox-launchpad-plugin/
/usr/share/doc/firefox-launchpad-plugin/copyright
/usr/share/doc/firefox-launchpad-plugin/changelog.gz