Thank you! I made some changes to the permission system so it's nicer to use, and added some documentation. I would suggest writing a bit more documentation next time, e.g. like I did in 7e5317d or 02727ac :-)

Thank you too for the updates and the quick merging :)
I will think about it next time ;)

Apparently this does not work, see the documentation for getActiveSessions:

This requires the Manifest.permission.MEDIA_CONTENT_CONTROL permission be held by the calling app. You may also retrieve this list if your app is an enabled notification listener using the NotificationListenerService APIs, in which case you must pass the ComponentName of your enabled listener.

However the MEDIA_CONTENT_CONTROL permission is only available to system apps (and apparently also debug apps, because while I was testing I didn't get any error whatsoever!). So we may want to try the alternative suggested above, however it seems overly complicated to use a listener service running in the background just to get a list of media apps... Gotta love Android 😫

Fixed in 4909bbb, apparently you can use AudioManager and that doesn't require any permission. Thanks to how well documented Android is, I only found out about this method in a kind-of unrelated StackOverflow question https://stackoverflow.com/q/67979372 . I tested on API 36 emulated, API 22 emulated and API 34 on-device and it seems to work.

Wow, well done!
I'm sorry I didn't know about this limit

Don't worry, I didn't know either and it worked without issues when I tested the debug build