/usr/ is in ruby-buff-extensions 2.0.0-1.
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/buff/
/usr/lib/ruby/vendor_ruby/buff/extensions/
/usr/lib/ruby/vendor_ruby/buff/extensions/boolean.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/hash/
/usr/lib/ruby/vendor_ruby/buff/extensions/hash/dotted_paths.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/hash/except.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/hash/key_transforms.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/hash/reverse_merge.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/hash/slice.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/hash.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/kernel/
/usr/lib/ruby/vendor_ruby/buff/extensions/kernel/reporting.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/kernel.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/object/
/usr/lib/ruby/vendor_ruby/buff/extensions/object/blank.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/object/try.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/object.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/string/
/usr/lib/ruby/vendor_ruby/buff/extensions/string/inflections.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/string.rb
/usr/lib/ruby/vendor_ruby/buff/extensions/version.rb
/usr/lib/ruby/vendor_ruby/buff/extensions.rb
/usr/lib/ruby/vendor_ruby/buff-extensions.rb
/usr/share/
/usr/share/doc/
/usr/share/doc/ruby-buff-extensions/
/usr/share/doc/ruby-buff-extensions/README.md
/usr/share/doc/ruby-buff-extensions/changelog.Debian.gz
/usr/share/doc/ruby-buff-extensions/copyright
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/buff-extensions-2.0.0.gemspec