Extension link: https://addons.mozilla.org/en-US/firefox/addon/wallabagger
Install the extension, and attempt to configure it. As an example server, you can use the server "app.wallabag.it". Click Check URL. Nothing happens, and there is no permissions prompt as expected.
Expected:
On Firefox, after entering the URL and picking "check URL", a permissions prompt is popped up:

More settings are then shown after this domain-specific permission request:

Interestingly, if you configure the plugin manually in Firefox, then export and load a configuration, it works fine in Orion - it just seems to be the logic handling this "Check URL" button and un-hiding the rest of the config settings that is the issue (i.e. cosmetic). I have tested the plugin in this mode and it functions just fine after you jump through the setup hoops 🙂