GeneXus generates an executable file for each Main Object that is defined, containing the object itself and all other objects called directly or indirectly by it.
For each Main object, you can define its title and its icon. You can also choose a generator to generate the object.
When a Main object is called from within another object, GeneXus generates a call to an executable file.
To set an object as a Main object, you have to configure its Main program property to True.
Main program property
Startup Object