I think metadata has another meaning too, but that may be the meaning they mean (that's an awful sentence, sorry).
I think it also means "information about". Ah, here's a definition:
met·a·da·ta
Noun
A set of data that describes and gives information about other data.
I mean, that is what you were talking about, but I guess you were talking about a specific instance of it, and I agree that probably is the one that was meant here.
Emma, one of the things I love about the advice and answering musings you give on here is that you are never prescriptive. You tend to talk around a subject and explain all the options. That gives a real feel and understanding to others (me) rather than a narrow rule.
Deb