It could have been in anyone of them, and even in a totally new rpy file that would have had only this line.
As long as it's inside a rpy file located somewhere inside the "/game/" directory or one of its sub directories, Ren'py don't care where the code is located. What matter is the name of the file (Ren'py will proceed them by alphabetical order) and the init level, when it's an init block.