On 2025-02-12 Wed 14:27 GMT-08, Hong Xu <hong@topbug.net> wrote:

> * src/fns.c (Fmapconcat): Explain that FUNCTION can return nil.
> ---
>  src/fns.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/src/fns.c b/src/fns.c
> index bee44b222c5e..f02a1b6838da 100644
> --- a/src/fns.c
> +++ b/src/fns.c
> @@ -3400,9 +3400,11 @@ SEQUENCE may be a list, a vector, a bool-vector, or a string.
>  Optional argument SEPARATOR must be a string, a vector, or a list of
>  characters; nil stands for the empty string.
>  
> -FUNCTION must be a function of one argument, and must return a value
> + FUNCTION must be a function of one argument, and must return either:

For some reason there is an extra space here. I've corrected this with
the attached patch.