Philipp Stephani wrote:
>
> Only in Emacs 28, because 26 will still have old-style backquotes only.

Ah, OK, I was turned around then: this variable is for forward-compatibility and
not backward. I suggest mentioning in the doc string that setting the variable
makes Emacs compatible with planned-for-28 behavior, and that the variable is
planned to go away in Emacs 28. (It's a temporary variable, so to speak....)