Muting the speakers when the mics are live, so you don’t get feedback from the speakers in certain use cases. It’s an option that you can turn on or off with some mixers.
Muting mixes when input channels are ‘open’ is not a feature built into the Qu, but can be achieved relatively easily with MIDI.
Using either a translation application on a connected computer (e.g. https://www.bome.com/products/miditranslator ) or hardware that can translate (e.g. https://www.bome.com/products/bomebox ) you can use one (just fader) or two (fader and mute) ‘if’ statements to trigger the mute for a mix (or mixes).
RE: Dante – as Steffen says, you’d need to look at the SQ range or above to make use of option cards, but you can use Dante Via with the Qu’s USB audio interface.