It was removed because rubygems was made to be required by default so it was now useless. The stdlib still contains `un.rb` though: https://github.com/ruby/rub

It was removed because rubygems was made to be required by default so it was now useless. The stdlib still contains `un.rb` though: https://github.com/ruby/ruby/blob/d428d086c23219090d68eb2d027498c6ea999b89/lib/un.rb#L12-L27 https://github.com/ruby/ruby/blob/d428d086c23219090d68eb2d02...