Quark is common in cuisine in German Speaking Countries. Quark is somewhat cheese-like but is not a cheese. However in some countries Quark is considered to be a fresh acid cheese or fermented milk that’s coagulated and strained. Traditional Quark doesn’t contain rennet but these days nobody gives a fork and you might find forking rennet in it. Usually no salt is added.
I tasted some last week. It FORKING looks and taste like forking sour cream.