I’m proud to say that I now know what a “twiddle-wakka” is. It is the notation ~> that we use in our Ruby-flavoured semver notation in Gemfile. Specifically, it means that the accepted version must be at the same level of the specified version. All sub-levels below the next increment of the current level are accepted. For example, ~> 2.0 means 2.0 <= VERSION < 2.1, while ~> 2.0.1 means 2.0.1 <= VERSION < 2.0.2.

Reference: http://guides.rubygems.org/patterns/

But seriously, now I know what a “twiddle-wakka” is. :D