How do you then grant Firefox write access to your Downloads folder, read access to folders on the fly when you want to upload a file, “general area only” locat

How do you then grant Firefox write access to your Downloads folder, read access to folders on the fly when you want to upload a file, “general area only” location information, access to the microphone and camera only during video conferencing, etc? You can do some of this with groups, but that’s difficult and runs into limitations pretty quick for even comparatively simple use-cases. And making a bunch of custom ab-hoc groups requires root access on top, when ideally a user should be able to manage fine-grained control without escalating their own privileges. Traditional POSIX file permissions are a huge blunt hammer that don’t scale well to the fine-grained type of access that things like iOS let you configure.