/usr/lib/ruby/ is in ruby-github-markup 1.3.3+dfsg-1build1.
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/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/github/
/usr/lib/ruby/vendor_ruby/github-markup.rb
/usr/lib/ruby/vendor_ruby/github/commands/
/usr/lib/ruby/vendor_ruby/github/commands/rest2html
/usr/lib/ruby/vendor_ruby/github/markup/
/usr/lib/ruby/vendor_ruby/github/markup.rb
/usr/lib/ruby/vendor_ruby/github/markup/command_implementation.rb
/usr/lib/ruby/vendor_ruby/github/markup/gem_implementation.rb
/usr/lib/ruby/vendor_ruby/github/markup/implementation.rb
/usr/lib/ruby/vendor_ruby/github/markup/markdown.rb
/usr/lib/ruby/vendor_ruby/github/markup/rdoc.rb
/usr/lib/ruby/vendor_ruby/github/markups.rb