- Edited
For example, when you're listening to music in a background tab and start watching a video in the active tab, instead of having the audio of both playing at the same time, the background audio would automatically mute and only the audio of the active tab would be playing.
Ideally, the background audio could also pause instead of mute, which should be technically feasible as well, I think.
This is just an idea regarding a small annoyance I encounter relatively often. I don't think any browser has such a feature yet.