/usr/ is in ruby-rack-mobile-detect 0.4.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/rack/
/usr/share/
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/1.9.1/
/usr/share/rubygems-integration/1.9.1/specifications/
/usr/share/rubygems-integration/1.9.1/specifications/rack-mobile-detect-0.4.0.gemspec
/usr/share/rubygems-integration/2.0/
/usr/share/rubygems-integration/2.0/specifications/
/usr/share/rubygems-integration/2.0/specifications/rack-mobile-detect-0.4.0.gemspec
/usr/share/doc/
/usr/share/doc/ruby-rack-mobile-detect/
/usr/share/doc/ruby-rack-mobile-detect/copyright
/usr/share/doc/ruby-rack-mobile-detect/changelog.Debian.gz
/usr/lib/
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/rack/mobile-detect.rb