You're right. I was trying to identify this function with $EvaluateModuleBody(loaderData.realm, mod); but that is not what it is. 

This function converts JS source into a call to $traceurRuntime.registerModule(name, fnc); where fnc is what js-loaders calls 'mod' I believe.

This function should not be called by Loader, but rather should be internal to LoaderHooks. (It has no equivalent in js-loaders).

done