RE: appt-display-format has bad Customize default and no value menu

[Drew Adams]

    > M-x customize-variable appt-display-format
    >
    > The standard value is `ignore', and this is a mismatch (`ignore' is
    > not a valid value).

    This is by design. ignore is a special value, meaning fall back on the
    previous (now obsolete) way of doing it, which used different
    variables. The available customize values represent the new way of
    doing it.

Sorry, I don't understand. How is a user supposed to use this or understand
it? Should users not try to customize this option? If they shouldn't, then
we should not enable customization for this variable at all. If they should,
then how do they do so?

If something about this has been deprecated, shouldn't the user be informed
of that in Customize?

If the default value causes Customize to somehow fall back to something that
is obsolete, isn't that a bug? Why should the default behavior call upon
something that is obsolete?

Sorry, I really don't understand what you are saying.

Looking at the doc string, presumably there should be a Value Menu that lets
you choose (only) valid values. There is no such menu.