/usr/ is in ruby-buff-shell-out 1.1.0-0ubuntu1.
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/buff/
/usr/lib/ruby/vendor_ruby/buff/shell_out/
/usr/lib/ruby/vendor_ruby/buff/shell_out/response.rb
/usr/lib/ruby/vendor_ruby/buff/shell_out/version.rb
/usr/lib/ruby/vendor_ruby/buff/shell_out.rb
/usr/lib/ruby/vendor_ruby/buff-shell_out.rb
/usr/share/
/usr/share/doc/
/usr/share/doc/ruby-buff-shell-out/
/usr/share/doc/ruby-buff-shell-out/README.md
/usr/share/doc/ruby-buff-shell-out/changelog.Debian.gz
/usr/share/doc/ruby-buff-shell-out/copyright
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/buff-shell_out-1.1.0.gemspec