There is a really interesting interview with Roman Elizarov, the language lead for Kotlin, on the Kotlin by JetBrains YouTube channel. Being a library developer in the past, Roman explains very clearly what the motivation is to include certain features in a library and when to add new features to the Kotlin programming language. He also shares some information about the Kotlin language team at JetBrains and what their focus is. Kotlin, being promoted as a modern language, also has to keep up with market trends in order to stay ‘modern’.