bug#74467: 31.0.50; org-protocol emacsclient.desktop change is not fully functional

bug#74467: 31.0.50; org-protocol emacsclient.desktop change is not fully functional

[Alexey Lebedeff via Bug reports for GNU Emacs, the Swiss army knife of text editors]

The change introduced by
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=65469 doesn't work anymore
in 'generic' desktop environment (as detected by 'xdg-open').

I assume it works in some desktop environments, where `xdg-open`
delegates opening to the desktop environment itself. But there is also a
`generic` version, which tries to implent XDG specification itself.

On 2023-10-03 there was a change introduced in xdg-utils
https://cgit.freedesktop.org/xdg/xdg-utils/commit/?id=b9d3ecf8180c57dbb5ca47253898ba0553e81c60
to more strictly follow xdg specification, and only pass URL-like
arguments to programs that explicitly requested this by using '%u' or
'%U' parameters.

'etc/emacsclient.desktop' uses '%F' parameter, which should be used for
programs that do not understand the URL syntax
(https://specifications.freedesktop.org/desktop-entry-spec/latest/exec-variables.html
- section about '%f', but also applies to '%F').

"x-scheme-handler/org-protocol" is the only URL-like protocol that's
mentioned in the 'etc/emacsclient.desktop', but 'xdg-open' refuses to
use it.

Just changing '%F' to '%U' in 'etc/emacsclient.desktop' is not possible,
as it allows 'xdg-open' to pass local files as "file:/" URL's if it
wants to.

One solution would be introducing separate  .desktop file
(i.e. 'etc/emacsclient-org-protocol.desktop'), analoguous to the already
existing 'etc/emacsclient-mail.desktop' (which uses '%u').


In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.43, cairo version 1.18.0)
Repository revision: 9cfd13ff44e8d6f56a1025207c833ab45a7d51ba
Repository branch: master
System Description: NixOS 24.05 (Uakari)