Kotlin and R8 - What's the Difference?

The mapping file you're talking about, that's the stuff that ProGuard used to have where if it renamed symbols to something obfuscated, it would record that in a mapping file. So we just used that information but now we're also reading these Kotlin source maps and putting that information in the mapping file as well so we can give developers better stack traces. That is in the most recent version of R8. If there's something that you're not explicitly keeping, then R8 will rename everything to use very short names because that uses less space. It will also do inlining to get rid of methods. And even merge classes together. The other interesting thing on Kotlin and R