Why two TRACK_MUTE_CHANGED events?

I noticed in the example code that there is a TRACK_MUTE_CHANGED event handler installed for both the conference as well as each remote track.

One is JitsiMeetJS.events.conference.TRACK_MUTE_CHANGED, and the other is JitsiMeetJS.events.track.TRACK_MUTE_CHANGED.

I’m wondering why that is. Is it necessary in order to capture all remote mute events?