Mullvad Browser is not listed as a possible default browser application for Gnome on Ubuntu / Fedora

In Ubuntu and Fedora (not verified yet in debiam), using the .rpm/.deb packages, when you go in Gnome to the default apps section in the settings, Mullvad Browser is not listed as a choice when using the dropdown. It's not there in Fedora KDE either.

See this screenshot from Ubuntu 24.04:

A cursory search seems to indicate we are missing some parameters in the .desktop file, and I tried the following. I seems to work, but it would need confirmation.

[Desktop Entry]
Type=Application
Name=Mullvad Browser
GenericName=Web Browser
Comment=Mullvad Browser is a privacy-focused web browser designed to minimize tracking and fingerprinting.
Categories=Network;WebBrowser;Security;
Exec=/usr/lib/mullvad-browser/start-mullvad-browser --detach %U
X-MullvadBrowser-ExecShell=/usr/lib/mullvad-browser/start-mullvad-browser --detach
Icon=mullvad-browser
StartupWMClass=Mullvad Browser
MimeType=text/html;text/xml;image/webp;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/about;