[Fontconfig] Questions about FcPattern etc

[Sundell Software]

I've been looking through the fontconfig code, and have a couple of questions:

Can/will FcPattern ever contain a FcValue of type FcPattern, or is it
safe to assume this will never be the case? I couldn't find any
FcPatternAdd* function to add FcPattern.

What is the typical use of FcPatternAdd with append, does this happen
relatively often?

FcCharSetFindLeafCreate(...) does not seem to check for
FC_REF_CONSTANT, though all the callers of it that i could find handle
this. I assume the caller is always responsible for this?

FcPatternGet(...) just copies the pointer when the FcValues is a
pointer. Is the client allowed to modify the content of this pointer,
and how does this relate to a frozen FcPattern?

Jari Sundell