OptionalconditionalClasses listed by exportClasses(): the S4 classes the package owns. Separated like exportedS4Methods.
Names listed by exportMethods(): S4 methods the package registered for one of its classes, which is a
different claim than an ordinary export (the package answers a generic, it does not define the function).
Only the context-parsed path (parseNamespaceComplex) tells these apart; the regex fallback folds
them into exportedFunctions.
Present only in complex parsed NAMESPACE files. Maps conditions to the parts they gate.