x1 is is made of/contains/is a quantity of a black/very-dark colored carbonated beverage/soda of cola-flavor, of brand x2.
Not any black, carbonated beverage, but one with cola-flavor, like Coca-Cola (=kokaKOlys), Pepsi, Julmust (=a soft drink that is mainly consumed in Sweden around Christmas;=(sfe'ero) xisyjbenunsla xeksodva) or similar. Another flavor may be added and expressed as a tanru, as long as the combination doesn't differ too much from the characteristics of xeksodva.