It means, we don't have any published documentation for accessing the microphone button via ECP. The problem with implementing something for an undocumented API is that if the API changes it would break your app. I wouldn't hold your breath for anything like this being published in the immediate future. I don't think we have a problem with you experimenting, but if you want to publish a Roku Channel that does this, I can't say one way or the other if we would publish it, would have to see what it does and what the content team thinks about it.
- Joel