The specification itself
is documentation.
edit: I mean, it’s not that I strongly care, but why not explain if you disagree? How exactly is a specification not a form of documentation?
The relevant definition for spec would probably be:
> a detailed description of the design and materials used to make something.
That sounds an awful lot like documentation.
Maybe you are implying that you can’t read it and then make your own implementation of that reading, but that’s not true. IANAL, but I’d be willing to bet my lawful ass it means you can’t reproduce the document for your own commercial implementation. Not that you can’t reference it. I don’t think “derivative” is that strong.