/usr/lib/ruby/ is in ruby-hpricot 0.8.6-5ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/1.9.1/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/hpricot_scan.so
/usr/lib/ruby/vendor_ruby/hpricot/
/usr/lib/ruby/vendor_ruby/hpricot.rb
/usr/lib/ruby/vendor_ruby/hpricot/blankslate.rb
/usr/lib/ruby/vendor_ruby/hpricot/builder.rb
/usr/lib/ruby/vendor_ruby/hpricot/elements.rb
/usr/lib/ruby/vendor_ruby/hpricot/htmlinfo.rb
/usr/lib/ruby/vendor_ruby/hpricot/inspect.rb
/usr/lib/ruby/vendor_ruby/hpricot/modules.rb
/usr/lib/ruby/vendor_ruby/hpricot/parse.rb
/usr/lib/ruby/vendor_ruby/hpricot/tag.rb
/usr/lib/ruby/vendor_ruby/hpricot/tags.rb
/usr/lib/ruby/vendor_ruby/hpricot/traverse.rb
/usr/lib/ruby/vendor_ruby/hpricot/xchar.rb