rdtool 0.6.38-3 (arm64 binary) in ubuntu xenial

 RD is multipurpose documentation format created for documentating Ruby and
 output of Ruby world.
 .
 You can embed RD into Ruby script. And RD have neat syntax which help you
 to read document in Ruby script. On the other hand, RD have a feature for
 class reference.
 .
 RDtool is one of frontends of formatter for RD. This package provides rd2
 command.