I didn't know about this!

It's interesting that "local-variable" and "instance-variable" are hyphenated, but "class variable" contains a space. I wonder why that is?

I'm not sure why, but all the source values are listed here: https://github.com/ruby/ruby/blob/1cc700907d3ad3368272488a6f...

Maybe someone knowledgeable in the underpinnings of Ruby will explain why "class variable" was not hyphenated.