/usr/ is in ruby-directory-watcher 1.5.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/
/usr/lib/ruby/vendor_ruby/directory_watcher.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/
/usr/lib/ruby/vendor_ruby/directory_watcher/collector.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/em_scanner.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/scanner.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/rev_scanner.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/scan_and_queue.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/scan.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/file_stat.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/event.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/version.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/logable.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/eventable_scanner.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/coolio_scanner.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/paths.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/configuration.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/threaded.rb
/usr/lib/ruby/vendor_ruby/directory_watcher/notifier.rb
/usr/share/
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/directory_watcher-1.5.1.gemspec
/usr/share/doc/
/usr/share/doc/ruby-directory-watcher/
/usr/share/doc/ruby-directory-watcher/copyright
/usr/share/doc/ruby-directory-watcher/changelog.Debian.gz
/usr/share/doc/ruby-directory-watcher/README.txt