This is one that drives me nuts on iOS. I'm forced to class dump and decompile to understand the issue or the undocumented behavior. In Android, it's easier because the source. Unfortunately it lags really far back from the binary release before it becomes open. It's frustrating. On the .NET stack, Microsoft listened and they include the source stubs in a download that Visual Studio will download. If you are stepping through into a system library, it shows you the actual source code (to level but it's better than nothing).