I wonder how accidental that feature is. It's certainly not something that Firefox can advertise, since other apps which did that have been kicked out off the Play Store.
Also, I also found that feature to be not very reliable since Android 6, which quite aggressively puts background apps to sleep (at least on my phone with "only" 2GB of RAM). I find that any extensive use outside Firefox will make the background playing stop rather quickly.
Also, I also found that feature to be not very reliable since Android 6, which quite aggressively puts background apps to sleep (at least on my phone with "only" 2GB of RAM). I find that any extensive use outside Firefox will make the background playing stop rather quickly.