bug#81606: Mojibake with UTF-8 file names

> Date: Sun, 16 Aug 2026 16:37:42 +0000
> Cc: [email protected], [email protected]
> From: Werner LEMBERG <[email protected]>
> 
> 
> >> Well, the AUCTeX documentation doesn't require it yet — otherwise I
> >> wouldn't have noticed the problem.  I think it's a good thing if
> >> Emacs has a heuristic fallback mechanism to handle the case without
> >> a `coding` cookie.
> > 
> > And for that case I think the recommendation should be to encode the
> > file name in UTF-8.
> 
> OK, so perhaps you can suggest better documentation?

I thought I already did, but here it is again:

  If you're using non-ASCII characters in the name of the master file,
  you should give Emacs a hint about the correct coding of the current
  file like this:
  
  @example
  %%% Local Variables:
  %%% coding: utf-8
  %%% TeX-master: "ä-master"
  %%% End:
  @end example

  In general, we recommend to use UTF-8 for any non-ASCII text.