open fun getOutputFile(): File
Overrides GeneratorTask.getOutputFile
Configures output *.iml file. It's optional because the task should configure it correctly for you (including making sure it is unique in the multi-module build). If you really need to change the output file name it is much easier to do it via the idea.module.name property.
Please refer to documentation in IdeaModule name property. In IntelliJ IDEA the module name is the same as the name of the *.iml file.