Sometimes we need to debug certain batch job execution. In AX 2012 we have to attached Visual Studio to the 'AOS' process and debug the IL code. It's pretty much the same still and got even easier because X++ now is a .NET language.
So navigate to Debug / Attach To Process in Visual Studio and make sure to select show processes from all users. The batch service has the obvious name Batch.exe (its location is C:\CustomerServiceUnit\DOBind\Packages\Cloud\AosWebApplication\
AosWebApplication.csx\roles\AosWeb\approot\bin – at least on locally deployed machines and this is only for informational purposes, usually you won’t need to know).
Attach to that process and be able to debug the X++ code that is executed there.