Lars Ingebrigtsen <larsi@gnus.org> writes:

> Mauro Aranda <maurooaranda@gmail.com> writes:
>
>> I attach a patch that should fix this (but that does not change the
>> way the characters are displayed) and that doesn't introduce the
>> breakage of Bug#3136 (for which I added a test).
>
> Thanks; applied to Emacs 28.

Thank you.

> The bits that remains to be fixed here is the display of the TAB/newline
> (etc.) characters?

Yes.  I think there were two suggestions, which if I'm not mistaken can
be summarized as:
- Display newline as \n, tab as \t, etc.
- Display newline as C-j (or ?\\C-j, or \\C-j, etc), tab as C-i, etc.

To those suggestions, I add one of mine:
- Display newline as ^J, tab as ^I, etc.

That is what Isearch does, and I think it would not be much of a
trouble to implement that.  Furthermore, we already display other
non-printable characters like that, so my suggestion would just
change newline and tab, I think.