bug#31725: Mysterious file in lispref manual's example(emacs-26.1)

[Takesi Ayanokoji]

Hi, Emacs developers.

In doc/lispref/files.texi: 1671-1674, example says about "foo1".

>>> start here

@group

(add-name-to-file "foo1" "foo3")

     @result{} nil

@end group

<<< end here

 But I could not find meaning of this file in this example's context.

Is this @group-block necessary? 

Thanks.

ayatakesi <ayanokoji.takesi@gmail.com>