Sort-of/yes, just found something in the docs while looking for another problem.
https://developer.amazon.com/public/solutions/devices/fire-tv/docs/amazon-fire-tv-sdk-frequently-asked-questions Q: How should I handle the TV being turned off/disconnected? A: The expected behavior for an HDMI disconnect is different for audio and video: ◾Apps that play video should pause playback when the TV is turned off or disconnected. When the TV output returns, playback should remain paused until the user presses PLAY. ◾Apps that play audio can continue to play if the TV is unavailable, but the device must must be connected with a TOSLINK (digital optical) audio connection for the audio to be heard. Listen for the AudioManager.ACTION_AUDIO_BECOMING_NOISY broadcast intent to test for HDMI changes.