I'll be teaching Advanced Type Mechanics in London on 10-11 Dec! This is a great opportunity to become an expert in Scala through the lens of its type system, and to learn all about existentials, variance, kinds, LUBs, unification & bounds! More info here: https://www.functionalscala.com/training
It's not a well-defined term but it covers the understanding of Scala's different types of types, and how they relate to each other and interact. As one example, I will explain the close relationship between bounded existential types and variance (after explaining what they are).