TYPE_VFIELD documentation

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

That field is documented as

    The @code{TYPE_VFIELD} is a compiler-generated field used to point to
    virtual function tables.  It may or may not appear on the
    @code{TYPE_FIELDS} list.  However, back ends should handle the
    @code{TYPE_VFIELD} just like all the entries on the @code{TYPE_FIELDS}
    list.

I don't understand.

First of all, what does "it" mean at the start of the second sentence?
It certainly doesn't mean the *field*, but instead means some tree node.
Which one?

The last sentence is totally incomprehensible to me.  Is TYPE_VFIELD
a pointer to a single node or a list of nodes?  If the latter, why is
it singular and how are the nodes chained?

Also, this doesn't give the most important information that it should, namely
for which tree codes TYPE_VFIELD is defined.

There are similar problems with TYPE_METHOD.