What happens when we want to wrap flat modules in an application but we have no process to start and thus no need for an application callback module?
After pulling our hair and crying in rage for a few minutes, the only other thing left to do is to remove the tuple {mod, {Module, Args}} from the application file. That's it. This is called a library application. If you want an example of one, the Erlang stdlib (standard library) application is one of these.
It shouldn't have this line:
https://github.com/isaksky/transit-erlang/commit/342c7ea40cce9cd6220fa1825d042cc2fca6bfb3
http://learnyousomeerlang.com/building-otp-applications