User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:87.0) Gecko/20100101 Firefox/87.0

Steps to reproduce:

• Use a linux distribution with DE (Desktop Environment) = Gnome Shell.
  • Fedora Workstation 34 was used for this test, but was also reproduced in other Linux based OS
• Install Firefox flatpak version: https://flathub.org/apps/details/org.mozilla.firefox
• Install extension: https://addons.mozilla.org/en-US/firefox/addon/gnome-shell-integration/
• Go to: https://extensions.gnome.org/
  • For installing/ enabling an extension:
    • Click in an extension's link
    • Click on the switch to the ON state
  • For disabling an extension:
    • Click in an installed extension's link
    • Click on the switch to the OFF state
  • For excluding an extension:
    • Click in an installed extension's link
    • Click on the X button

Actual results:

• A banner with following message appears: "Although GNOME Shell integration extension is running, native host connector is not detected. Refer documentation for instructions about installing connector."
• Website doesn't recognize the version of Gnome Shell is being used to filter extensions compatible with current version
• When in a extension's page, the ON/OFF switch and the X button doesn't appear

Expected results:

• No error messages appear
• website recognize Gnome Shell version
• Being able to install/ enable/ disable/ remove extension

Additional Information (field hidden from bug entry form):

• Following the same steps with the Firefox provided by the distribution errors doesn't occour
• Issues were open in the official extension's Gitlab page. According with the response from the maintainer to the issue 22, this is not an extension issue.
  • https://gitlab.gnome.org/GNOME/chrome-gnome-shell/-/issues/5
  • https://gitlab.gnome.org/GNOME/chrome-gnome-shell/-/issues/22
  • https://gitlab.gnome.org/GNOME/chrome-gnome-shell/-/issues/29
• A Topic was open in the Flathub Discourse to try to aggregate information and search for some people interested to help:
  • https://discourse.flathub.org/t/gnome-extension-compatibility-issue-internet-browser/1341

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Gtk' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

I'm not sure this will even work based on Flatpak architecture? The Flatpak would need to communicate with an application outside of the Flatpak.

Sorry, I don't fully understand the subject, but I can point some things:

• According to Pipe app project website, it is just a frontend for a daemon that must run on the user's machine, so a flatpak app can somehow communicate outside the container. And it's available on Flathub
• The dconf app changes several gnome-shell settings, including editing settings for each extension via the path of dconf database /org/gnome/shell/extensions/[extension_ID]/[key] and enabling/disabling extensions by changing the value of the key /org/gnome/shell/enabled-extensions. And it's available on Flathub
• A manual way to install extensions in gnome-shell is to place the folder containing their files in ~/.local/share/gnome-shell/extensions. And having access to a machine's folder I'm sure it's possible through portals, and if not possible, using filesystem access. Here is the portal's documentation

There is also the possibility to run commands outside the sandbox with the command flatpak-spawn.

Here is a pull request to Obs Studio as example that uses it. It’s description show a better introduction to the subject. Here is it's manifest.

If you have any technical questions, you can create a topic in https://discourse.flathub.org/c/general/. People will try to help.

There's currently no portal for the native messaging hosts so that's why it does not work. The application in flatpak cannot run commands on host. So we need a dbus api for that first. There's been some initiative from the Ubuntu guys, discussed there:
https://forum.snapcraft.io/t/native-messaging-support-in-strictly-confined-browser-snaps/26849