[AUCTeX] Follow-up: How to modify TeX-view-program-selection

[Greg Bognar]

I've just realized that

(setq TeX-view-program-selection '((output-pdf "zathura")))

doesn't work either.  It now complains that

Unknown "zathura" viewer. Check the `TeX-view-program-selection' variable

So I'm obviously on the wrong track.  (Until now, I have launched a PDF viewer
manually, so I haven't run into this problem.)