I have a desktop that is running KDE and an laptop that is running Gnome. I use the Firefox Sync service to sync my bookmarks and extensions across computers. This extension emits a "Failed to Connect to Native Host" notification whenever I am using a computer other than my KDE machine. I believe there are two different solutions to this problem: - Find out how to determine if the user is on a device other than KDE - Instead of using a notification, use another method to notify the user. I believe Firefox allows extension devs to show errors on the about:addons page so perhaps that is a solution.
I see your point. However,you could use plasma-browser-integration on any Linux desktop. Not sure how to detect a Plasma session from the browser. The error message is on purpose so it's not "silently not working". I disabled it for non-Linux so it wouldn't show up when synced to e.g. Windows, not sure how to proceed here.
*** Bug 401202 has been marked as a duplicate of this bug. ***
In the upcoming version error reporting has been improved: Only a toolbar icon is shown which is crossed out in case the extension isn't supported or failed to start for whatever reason. This should make the experience when the extension is synced to non-supported devices a lot nicer.