Show battery level in default sink change OSD
It's useful to quickly see the battery status when switching to that device.
Needs newer PulseAudio. Sadly, getting this percentage in battery monitor (and subsequent low battery warnings) you need to run bluez with -E (experimental) option. But with it that part then "just works". Could be useful to add it to the device name in the volume popup, too, since that info comes from PulseAudio then.