It's not available indeed. Not to have this option is acceptable if no OnPublish timer will run.

That in itself is a huge security issue. Someone with bad intent could put malicious code in an "OnPublish" timer and there would be no defense against it. Excellent remark Daniël.

The worst that happens with several demo apps is that it creates a lot of data and users on first publish.

There's not even a way to see the C# project code for external logic components.  There's an option to share a git link to the code, but no way to tell if that's really the actual code in the component or not!