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Xfce4 opening links in Chromium despite Firefox having been set as the default browser

Debian

Installing a laptop with the shiny new Debian Bookworm release finds a few interesting things broken that I probably had fixed in the past already on the old laptop.

One, that was increadibly unintuitive to fix, was lots of applications (like xfce4-terminal or Telegram) opening links in Chromium despite Firefox being set as the preferred webbrowser everywhere.

update-alternatives --config x-www-browser was pointing at Firefox already, of course.
The Xfce4 preferred application from settings was Firefox, of course.
xdg-mime query default text/html delivered firefox-esr.desktop, of course.

Still nearly every link opens in ███████ Chromium...

As usually the answer is out there. In this case in a xfce4-terminal bug report from 2015.

The friendly "runkharr" has debugged the issue and provides the fix as well. As usually, all very easy once you know where to look. And why to hate GTK again a bit more:

The GTK function gtk_show_uri() uses glib's g_app_info_launch_default_for_uri() and that - of course - cannot respect the usual mimetype setting.

So quoting "runkharr" verbatim:

1. Create a file `exo-launch.desktop´ in your `~/.local/share/applications´ directory with something like the following content:

    [Desktop Entry]
    Name=Exo Launcher
    Type=Application
    Icon=gtk-open
    Categories=Desktop;
    Comment=A try to force 'xfce4-terminal' to use the preferred application(s)
    GenericName=Exo Launcher
    Exec=exo-open %u
    MimeType=text/html;application/xhtml+xml;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ftp;application/x-mimearchive;
    Terminal=false
    OnlyShowIn=XFCE;

2. Create (if not already existing) a local `defaults.list´ file, again in your `~/.local/share/applications´ directory. This file must start with a "group header" of

    [Default Applications]

3. Insert the following three lines somewhere below this `[Default Applications]´ group header [..]:

    x-scheme-handler/http=exo-launch.desktop;
    x-scheme-handler/https=exo-launch.desktop;
    x-scheme-handler/ftp=exo-launch.desktop;

And ... links open in Firefox again. Thank you "runkharr"!

Getting gpg to import signatures again

Open Source

The GnuPG (gpg) ecosystem has been played with a bit in 2019 by adding fake signatures en masse to well known keys. The main result is that the SKS Keyserver network based on the OCaml software of the same name is basically history. A few other keyservers have come up like Hagrid (Rust) and Hockeypuck (Go) but there seems to be no clear winner yet. In case you missed it in 2019, see my take on cleaning these polluted keys.

Now the changed defaults in gpg to "mitigate" this issue are trickling down to even the conservative distributions. Debian Bullseye has self-sigs-only on gpg 2.2.27 and it looks like Debian Bookworm will get gpg 2.2.40. This would add import-clean but Daniel Kahn Gillmor patched it out. He argues correctly that this new default could delete data from good locally stored pubkeys.

This all ends in you getting some random combination of self-sigs-only and / or import-clean depending on which Linux distribution and version you happen to use.

Better be explicit. I recommend to add:

# disable new gpg defaults
keyserver-options no-self-sigs-only
keyserver-options no-import-clean

to your ~/.gnupg/gpg.conf to make sure you can manage signatures yourself and receive them from keyservers or local imports as intended.

In case you care: See info gnupg --index-search=keyserver-options for the fine documentation. Of course apt install info first to be able to read info pages. 'cause who would still used them in 2023? Oh, wait...