/usr/ is in lightning-l10n-nb-no 1:52.9.1-1~deb9u1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/lightning/
/usr/lib/lightning/extensions/
/usr/lib/thunderbird/
/usr/lib/thunderbird/extensions/
/usr/share/
/usr/share/doc/
/usr/share/doc/lightning-l10n-nb-no/
/usr/share/doc/lightning-l10n-nb-no/changelog.Debian.gz
/usr/share/doc/lightning-l10n-nb-no/copyright
/usr/share/lightning/
/usr/share/lightning/extensions/
/usr/share/lightning/extensions/langpack-nb-no@lightning.debian.org/
/usr/share/lightning/extensions/langpack-nb-no@lightning.debian.org/chrome/
/usr/share/lightning/extensions/langpack-nb-no@lightning.debian.org/chrome/nb-NO.jar
/usr/share/lightning/extensions/langpack-nb-no@lightning.debian.org/chrome.manifest
/usr/share/lightning/extensions/langpack-nb-no@lightning.debian.org/install.rdf
/usr/share/lightning/extensions/langpack-nb-no@lightning.debian.org/uninstall/
/usr/share/lightning/extensions/langpack-nb-no@lightning.debian.org/uninstall/Uninstall
/usr/share/lintian/
/usr/share/lintian/overrides/
/usr/share/lintian/overrides/lightning-l10n-nb-no
/usr/lib/lightning/extensions/langpack-nb-no@lightning.debian.org
/usr/lib/thunderbird/extensions/langpack-nb-no@lightning.debian.org