Consider migrating the default browser (Firefox) to a Flatpak

Removing Firefox from the base image is a frequent request. The main benefit would be easier integration for openh264 support via a Flatpak extension.

This is unfortunately not easy for several reasons:

• Firefox as packaged in Flatpak does not cover the same functionality as the RPM/base image installed one
• We will have to figure out a migration process for existing users that will "loose" their browser once we remove it from the base image.

See:

• https://github.com/fedora-silverblue/issue-tracker/issues/288
• fedora/sigs/flatpak/fedora-flatpaks#13

Non exhaustive list of things to do to make that happen:

• Implement a fallback default browser that installs Firefox again when no browser is available
• Actual change to include the Flatpak by default in Silverblue & Kinoite
• Migration of settings and data for existing users
• Fedora change request and announcement blog post on the Fedora Magazine
• How will users manage GNOME extensions on Silverblue:
  • https://github.com/flatpak/xdg-desktop-portal/pull/705
  • https://github.com/fedora-silverblue/issue-tracker/issues/399

List of optional things that would be good to have:

• Figure out the openh264 story for the Fedora Flatpak