https://en.m.wikipedia.org/wiki/Master_Quality_Authenticated
Basically trickery with alleged lossless, but it is not even close to lossless and you need very special players that can unfold MQA. Tidal got a lot of criticism for it and eventually switched away to FLAC…but the way they handled it was pretty bad and it still brushes me the wrong way.
Because it works and provides a use case. Most “simpletons” do not want to invest any more time in than putting some Account Data and start watching netflix or whatever. “We” (e.g. the people that care about data privacy and stuff) never have been okay with that shit…