/usr/ is in exim4-daemon-heavy 4.90.1-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/bin/
/usr/lib/
/usr/lib/exim4/
/usr/lib/exim4/local_scan/
/usr/sbin/
/usr/sbin/exim4
/usr/share/
/usr/share/bug/
/usr/share/bug/exim4-daemon-heavy/
/usr/share/bug/exim4-daemon-heavy/script
/usr/share/doc/
/usr/share/doc/exim4-daemon-heavy/
/usr/share/doc/exim4-daemon-heavy/EDITME.exim4-heavy.gz
/usr/share/doc/exim4-daemon-heavy/copyright
/usr/share/lintian/
/usr/share/lintian/overrides/
/usr/share/man/man8/runq.8.gz
/usr/share/lintian/overrides/exim4-daemon-heavy
/usr/share/man/
/usr/share/man/man8/
/usr/bin/mailq
/usr/bin/newaliases
/usr/lib/exim4/exim4
/usr/lib/sendmail
/usr/sbin/exim
/usr/sbin/rmail
/usr/sbin/rsmtp
/usr/sbin/runq
/usr/sbin/sendmail
/usr/share/doc/exim4-daemon-heavy/NEWS.Debian.gz
/usr/share/doc/exim4-daemon-heavy/README.Debian.gz
/usr/share/doc/exim4-daemon-heavy/changelog.Debian.gz
/usr/share/doc/exim4-daemon-heavy/changelog.gz
/usr/share/man/man8/exim4.8.gz
/usr/share/man/man8/mailq.8.gz
/usr/share/man/man8/newaliases.8.gz
/usr/share/man/man8/rmail.8.gz
/usr/share/man/man8/rsmtp.8.gz
/usr/share/man/man8/sendmail.8.gz