completion-all-completions-with-base-size

[Eli Zaretskii]

This NEWS entry:

    *** `all-completions' may now return the base size in the last cdr.
    Since this means the returned list is not properly nil-terminated, this
    is an incompatible change and is thus enabled by the new variable
    completion-all-completions-with-base-size.

is inaccurate: `all-completions' does not take into account the value
of `completion-all-completions-with-base-size'.  Only
`completion-all-completions' and a couple of internal functions
consult that variable.  But `completion-all-completions' is not
documented in the ELisp manual, as are most of other APIs in
minibuffer.el (should they be documented?), so it sounds like the
above NEWS entry does not warrant any documentation in the manuals?
Why then it was added to NEWS?