/usr/ is in ruby-rack-contrib 1.3.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/rack/
/usr/lib/ruby/vendor_ruby/rack/contrib/
/usr/lib/ruby/vendor_ruby/rack/contrib/callbacks.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/static_cache.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/simple_endpoint.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/bounce_favicon.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/route_exceptions.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/evil.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/locale.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/lighttpd_script_name_fix.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/response_cache.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/relative_redirect.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/post_body_content_type_parser.rb
/usr/share/rubygems-integration/all/
/usr/lib/ruby/vendor_ruby/rack/contrib/csshttprequest.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/common_cookies.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/not_found.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/proctitle.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/response_headers.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/time_zone.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/expectation_cascade.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/garbagecollector.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/printout.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/host_meta.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/mailexceptions.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/signals.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/runtime.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/nested_params.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/accept_format.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/sendfile.rb
/usr/share/rubygems-integration/all/specifications/
/usr/lib/ruby/vendor_ruby/rack/contrib/try_static.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/jsonp.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/cookies.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/deflect.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/access.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/enforce_valid_encoding.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/config.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/profiler.rb
/usr/lib/ruby/vendor_ruby/rack/contrib/backstage.rb
/usr/lib/ruby/vendor_ruby/rack/contrib.rb
/usr/share/
/usr/share/doc/
/usr/share/doc/ruby-rack-contrib/
/usr/share/doc/ruby-rack-contrib/copyright
/usr/share/doc/ruby-rack-contrib/changelog.gz
/usr/share/doc/ruby-rack-contrib/README.md.gz
/usr/share/doc/ruby-rack-contrib/changelog.Debian.gz
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/specifications/rack-contrib-1.3.0.gemspec