Re: [help-texinfo] Re: @heading after @node?

[Karl Berry]

        @node foo
        @heading foo

    remains forbidden,

It isn't forbidden.  It just doesn't cause a node/section association.

    would be to say that a @node line must immediately be followed by
    @section or @unnumberedsec (or equivalents of other levels).

@node can be followed by arbitrary text.  There is no requirement for
sectioning commands at all.  (Unfortunately.)