Hmm, it's not made from either of those recipes as the green colour of the mint would impart at least a tinge of green to the sauce and/or the mint leaves would remain visible. There would be no reason for declaring mint as an ingredient. I doubt it's mint extract as there would be no reason for not declaring it on the packaging in the form of "contains natural flavouring" etc. So what are we left with?
The chances are that the yogurt has been mixed with, wait for it, N-Ethyl-2-isopropyl-5-methylcyclohexanecarboxamide. This substance is one of a group of chemicals called methane monoterpinoids that are used in the food industry as flavouring. Many, including this one, are generally regarded as safe for human consumption. This particular one is ideal for use in mint and yogurt sauce as it has minty smell and a cooling effect in the mouth when used on curries etc. due to clever chemical reaction when it touches the tongue. It's a white powder that wouldn't colour the yogurt in any way and it's cheap.
I'd stick to the type where you can see the mint particles if I were you but as I said, it does the job.