Anything that is not hardcoded is technically input. But there is a reason we have a word for config. It's a specific kind of input: it feeds the boostrapping

Anything that is not hardcoded is technically input. But there is a reason we have a word for config. It's a specific kind of input: it feeds the boostrapping state of your program, it's not the main data your program process. The difference is important: structure, complexity and dynamism requirements are not the same.