I have every episode of Star Trek, several times for the 90s series. I don̵
Users who access the feature can see a large, friendly “Video Out” button. There is also a setting option that allows you to always turn the Audio Only mode on or off by default, or activated when you connect headphones or speakers.
Based on a short survey from the Review Geek team, it seems the feature is very slow to roll out as none of us have it. And we don’t know if a video with audio only will play in the background while you’re doing other things on Android (which would make sense) or if it will show up in a mini player window with a blank video (making a little less sense). It’s also not clear if streaming audio alone uses less data, which would be really cool if you want to listen to shows while on the go.
Presumably the audio only option will hit iOS at some point.
Source: Android Police