Re: Lisp manual is incomplete w.r.t. mode-line-format

[Richard Stallman]

    But the manual does not say anything about an unbound symbol in a
    (SYMBOL THEN [ELSE]) construct.  Experiment shows that when SYMBOL is
    void the ELSE element is used, rather than ignoring the entire
    construct.  Is that the correct behavior?  It should be documented.

Could someone verify that this is still true in the current sources?
Then I will document it.