For non-trivial programs the configuration space is so large that it's impractical to test every single configuration during development, so instead the operators are expected to test before putting into production.
So an INI file is code too?
Generally people think of code as being executed and doing some task. Can you use JSON to compute prime numbers?
Or is code now any structured data read by a program?
It is all up to the interpreter you give the code too. Your program that takes yaml config is an interpreter, though probably a very limited one and hopefully a safe one (though that needs to be tested / checked for to be more sure of)
When I observe the world, I come to a different conclusion. I see people including non-programmers talk about HTML as code. I see software packages like editors that say they deal with code, and it's not about T-c languages. Encyclopedias and dictionaries record the definition of code very broadly as interpretation of information, not T-c languages specifically.
I’m amazed this is even a question. Of course it is! It’s explicitly defined as an interchange format. Its only purpose is as code.
> In an informal setting.
What formal settings are we supposed to be satisfying?
> If you are, for example, writing documentation, please refrain from doing so.
I respectfully decline this request.
> But that's entirely situational. A yaml snippet containing my list of groceries is not code.
> Yaml doesn't have to be classified as code to be testable. "We should have tests for our configuration files" is perfectly reasonable.
I mean this with kindness and sincerity, if a little incredulity: maybe your definition of code is ambiguous and warrants some clarification. To me, this isn’t a holistic definition but it certainly seems like a relevant starting point: if it has a syntax specification that machines can use, it’s code.