When Google signs your app, they build the .apk bundle. JVM bytecode can be optimized without needing the source (Java or Kotlin). They actually build & sign se

When Google signs your app, they build the .apk bundle. JVM bytecode can be optimized without needing the source (Java or Kotlin). They actually build & sign several different bundles for different devices, optimizing each for the particular target (API level), and then serve the correct one when it's installed via the Play store. When they do this, they optimize out any calls to legacy API functions, and don't build bundles for those API versions.