"1 kg of drugs containing 30 g of heroin"? So is that 30 grams of heroin plus filler, or is it 1 kg of something else that's been adulterated with heroin? What

"1 kg of drugs containing 30 g of heroin"? So is that 30 grams of heroin plus filler, or is it 1 kg of something else that's been adulterated with heroin? What does "drugs" mean?