For example, RSpec 3.4 will use `coderay` for syntax highlighting [1] if it’s available, but doesn’t make `coderay` a dependency of the `rspec` gem. That’s great! People who want syntax highlighting can install the extra gem and get the benefit; people who don’t care about syntax highlighting, or who don’t think it’s worth adding a dependency, can carry on as before.
Why didn’t you do the same with `capistrano-harrow`? (I have no investment in the answer, just trying to clarify what others are asking about here.)
[1] http://rspec.info/blog/2015/11/rspec-3-4-has-been-released/#...