/usr/lib/ruby/ is in ruby-tilt 2.0.0+really1.4.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/tilt.rb
/usr/lib/ruby/vendor_ruby/tilt/
/usr/lib/ruby/vendor_ruby/tilt/markaby.rb
/usr/lib/ruby/vendor_ruby/tilt/yajl.rb
/usr/lib/ruby/vendor_ruby/tilt/asciidoc.rb
/usr/lib/ruby/vendor_ruby/tilt/radius.rb
/usr/lib/ruby/vendor_ruby/tilt/textile.rb
/usr/lib/ruby/vendor_ruby/tilt/haml.rb
/usr/lib/ruby/vendor_ruby/tilt/plain.rb
/usr/lib/ruby/vendor_ruby/tilt/css.rb
/usr/lib/ruby/vendor_ruby/tilt/liquid.rb
/usr/lib/ruby/vendor_ruby/tilt/erb.rb
/usr/lib/ruby/vendor_ruby/tilt/nokogiri.rb
/usr/lib/ruby/vendor_ruby/tilt/etanni.rb
/usr/lib/ruby/vendor_ruby/tilt/rdoc.rb
/usr/lib/ruby/vendor_ruby/tilt/wiki.rb
/usr/lib/ruby/vendor_ruby/tilt/builder.rb
/usr/lib/ruby/vendor_ruby/tilt/csv.rb
/usr/lib/ruby/vendor_ruby/tilt/template.rb
/usr/lib/ruby/vendor_ruby/tilt/markdown.rb
/usr/lib/ruby/vendor_ruby/tilt/coffee.rb
/usr/lib/ruby/vendor_ruby/tilt/string.rb