bug#18132: Time for a smarter dired-guess-shell-alist-default? (dired-x.el)

[Juri Linkov]

> These days, there are mature programs for launching an arbitrary file with
> an appropriate viewer: run-mailcap (which is mature to the point of
> obsolescence) and

run-mailcap is fully supported by shell-command and async-shell-command where
the list of available commands can be accessed using M-n in its minibuffer.

> xdg-open on GNU systems; open on Mac OS X; start on MS Windows).

xdg-open is a single command that is too easy to add to the top of this list.