[BUG] Cannot install Flatpaks from the web using GNOME Software

[aral]

Summary

GNOME Software fails with “Failed to install file: not supported” error when opening a flatpakref file downloaded from the web.

Installing Flatpaks from the web site of the app author themselves is a decentralised way to install applications and should be supported as a first-class installation method.

To Reproduce

1. Download a flatpakref file. e.g., https://flatpak.brixit.nl/switcher-stable.flatpakref for https://openswitcher.org/ (a free and open Atem Mini Pro switcher app)
2. Double click the downloaded file to open it in GNOME Software (default action)

What should happen

The app should install.

What actually happens

A cryptic/terse error is shown in GNOME Software: “Failed to install file: not supported.”

Workaround

Installing from the flatpakref file succeeds from the command-line:

flatpak install switcher-stable.flatpakref

Screenshots

OS version

State: idle
BootedDeployment:
● fedora:fedora/36/x86_64/silverblue
                   Version: 36.20220425.n.0 (2022-04-25T08:12:33Z)
                BaseCommit: aed492e0e146c40c8ef503f3240748611df5e18f18d30ae5ee8c68a347f15600
              GPGSignature: Valid signature by 53DED2CB922D8B8D9E63FD18999F7CBF38AB71F4
           LayeredPackages: fish gnome-console gnome-tweak-tool gstreamer1-plugin-openh264 langpacks-en lm_sensors
                            mozilla-openh264

[travier]

Fedora 36 is about to go EOL so I'll close this issue. Please provide updated information if this is still an issue.

[travier]

This is the issue tracker for Fedora Silverblue. Please report your issue to the correct tracker.