[emacs-w3m:13870] Re: Emacs-w3m/Emacs (?) bug with saved buffer and undo?

In [emacs-w3m:13869]
On Sat, 28 May 2022 05:00:37 +0200, Emanuel Berg wrote:
> Navigate to a page, e.g. https://dataswamp.org/~rjc/motd.txt
> Save as motd.txt in ${HOME}.
> Type something.
> Do M-x undo RET
> It says "undo-start: No undo information in this buffer"

(add-hook 'after-save-hook #'buffer-enable-undo)

Undo is disabled in the *w3m* buffer, as many buffers that don't
intend to edit are, and its state is kept in *the buffer* even
if it is saved to a file using `write-file' and the like.