/usr/ is in ruby-websocket-extensions 0.1.2-1.
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/websocket/
/usr/lib/ruby/vendor_ruby/websocket/extensions.rb
/usr/lib/ruby/vendor_ruby/websocket/extensions/
/usr/lib/ruby/vendor_ruby/websocket/extensions/parser.rb
/usr/share/
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/websocket-extensions-0.1.2.gemspec
/usr/share/doc/
/usr/share/doc/ruby-websocket-extensions/
/usr/share/doc/ruby-websocket-extensions/copyright
/usr/share/doc/ruby-websocket-extensions/changelog.Debian.gz
/usr/share/doc/ruby-websocket-extensions/README.md.gz