While exploring the CoreAudio HAL object tree, I came across two mysterious boolean controls that are exposed on the built-in microphone and the built-in output on my MBP with macOS 10.13 but don't appear anywhere in the documentation or system framework headers.
On the built-in mic, the control's class FourCharCode is 'donz', it's a subclass of 'togl' (kAudioBooleanControlClassID), it's set to true and is read-write.
On the built-in output, the control's class FourCharCode is 'evis', this one too is a descendant of 'togl', it's set to false and is read-write.
I'm curious if anybody else has bumped into these or know anything about their purpose.
