1.4.2 requires a mechanism to turn off "background audio that plays automatically, without requiring the user to turn off all audio". This is good except that "background audio" is not defined. Is it audio that is played at the same time as other audio, but is considered to be less important (i.e. background behind other audio)? Or Is it audio that is purely decorative and/or atmospheric, but not required for understanding or use of the web unit (regardless of whether other audio is playing)?
Define "background audio", or change "background audio" to either "audio" or "purely decorative audio".
Good point. We have revised the success criterion 1.4.2 to read, "1.4.2 If any audio plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume which can be set independently of the system volume."