What's the source of truth for deciding whether it was friendly fraud or not? Is it the chargeback reason code? As far I know there isn't a specific reason cod

What's the source of truth for deciding whether it was friendly fraud or not? Is it the chargeback reason code? As far I know there isn't a specific reason code for "friendly fraud" (i.e. banks are passing along chargebacks telling you as a merchant that they think it's not actual fraud) and more often than not, especially having worked on this problem at scale in the past, friendly fraud chargebacks just come back with a "this is fraud" reason code.