/usr/ is in ruby-mixlib-authentication 1.3.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/share/
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/mixlib-authentication-1.3.0.gemspec
/usr/share/doc/
/usr/share/doc/ruby-mixlib-authentication/
/usr/share/doc/ruby-mixlib-authentication/README.rdoc
/usr/share/doc/ruby-mixlib-authentication/copyright
/usr/share/doc/ruby-mixlib-authentication/changelog.Debian.gz
/usr/lib/ruby/vendor_ruby/mixlib/
/usr/lib/ruby/vendor_ruby/mixlib/authentication.rb
/usr/lib/ruby/vendor_ruby/mixlib/authentication/
/usr/lib/ruby/vendor_ruby/mixlib/authentication/digester.rb
/usr/lib/ruby/vendor_ruby/mixlib/authentication/http_authentication_request.rb
/usr/lib/ruby/vendor_ruby/mixlib/authentication/signatureverification.rb
/usr/lib/ruby/vendor_ruby/mixlib/authentication/signedheaderauth.rb