We can have a look at FcPattern on the output with FcPatternPrint() though, there are no way to peek around it programmatically. there are no function what kind of objects FcPattern has, so one can't obtain the objects efficiently with FcPatternGet*(). that would be nice if there are any API available for that purpose.
Yes, I agree that this is a gap in the API.
the proposed changes to add some APIs to obtain things from FcPattern:
merged this changes with some clean up and bug fixes because of the need of access to FcPattern iteratively.