Currently, the [Other Types](https://docs.scala-lang.org/scala3/book/types-others.html) page of Scala 3 Book links to the language specification for literal and refined types. Descriptions for: - higher-kinded types, - literal/singleton types (why the different names?), - refinement types, are missing from Scala 3 Reference. Existential types are listed as a dropped feature and the description for kind polymorphism lacks an example.