Open with BBC America App
I don't know how this happened but every page I visit on Firefox for Android suddenly has the option to open in the BBC America app. Even here on the Mozilla support site!
Additional System Details
- User Agent: Mozilla/5.0 (Android 8.0.0; Mobile; LG-H931; rv:63.0) Gecko/63.0 Firefox/63.0
I would check to see if the Beeb app has been set as a browser app somehow on your device under Settings → Apps. Or possibly open the Beeb app and look in it's settings.