I think it would be helpful under the definition of personal information, which is broad enough to capture it. It's identifiable information, so in many contexts metadata would definitely fit as identifiable information. It would be helpful to clarify it by saying, “for instance, it includes...”, and when you have the non-exhaustive list, to put that in. It's interpretatively helpful.
The caveat then is how you define metadata. If you used some kind of general thing, such as “this includes information about information”, or something like that....