I'm using IDEA 13 EAP + Kotlin plugin for android development and I see that application and kotlin library sources are placed into resulting .apk. What is the purpose for doing this?
I think it's just a bad side effect of the way the build works right now. I always remove the .kt files and script.xml from my apks before signing and zipaligning.
Also you can use Android Studio with Gradle and kotlin-plugin for development: there is no this issue.