Jet vs Kotlin naming

What is "Jet"? What and when should I use it in class names?

"Jet" is the first codename we used for Kotlin. It is used historically to name PSI classes (nodes in the parse tree) and some IDE classes + there's JetType to avoid confusion with ASM's Type.

A good rule of thumb is not to use this prefix unless all other classes in the same package have it.

Got it. Thanks!