Robert Haas <robertmhaas@gmail.com> writes:
> I find the idea of things being intentionally undocumented quite
> difficult.  How is someone coming along supposed to know which things
> are intentionally undocumented and which things are unintentionally
> undocumented?
They should assume the lack of documentation is intentional.  Six or
seven years ago your argument might have held some water, but we've
been quite rigorous about requiring externally-visible features to be
documented from the get-go.
            regards, tom lane