The localService read-only property of the SpeechSynthesisVoice interface returns a Boolean indicating whether the voice is supplied by a local speech synthesizer service (true), or a remote speech synthesizer service (false.)
The voiceURI read-only property of the SpeechSynthesisVoice interface returns the type of URI and location of the speech synthesis service for this voice.
The kinds read-only property of the TrackDefault interface returns default kinds for an associated SourceBuffer to use when an initialization segment does not contain label information for a new track.
The label read-only property of the TrackDefault interface returns the default label for an associated SourceBuffer to use when an initialization segment does not contain label information for a new track.
The language read-only property of the TrackDefault interface returns a default language for an associated SourceBuffer to use when an initialization segment does not contain language information for a new track.
The type read-only property of the TrackDefault interface returns the type of track that this SourceBuffer's media segment data relates to (i.e. audio, video, or text track.)