bug#39865: 28.0.50; Emacs crash

[Eli Zaretskii]

> From: Vinicius José Latorre <viniciusjl@gmail.com>
> Date: Thu, 5 Mar 2020 19:21:22 -0300
> Cc: 39865@debbugs.gnu.org
> 
> I found this line in my ~/.emacs that causes the crash:
> 
> (push '(font-backend xft x) default-frame-alist)

OK, then the crash is a known problem: you cannot change the font
backend once the session started, you can only do that in X resources.
Previously, XFT was your original backend, but now it's HarfBuzz.

Why are you doing this?  What happens/doesn't work if you remove this
line?