UTXOs in Profit, as the name suggests, represents the absolute number of UTXOs in a given network which are currently in profit (i.e. the price at the time they were created is lower than the current price).
This metric is helpful in highlighting market tops by suggesting when investors might be close to taking profits.
It is important to note that unlike Unrealized Profit, UTXOs in Profit does not account for the amount of profit - only the binary case of whether or not the UTXO is in profit.
UTXOs in Profit is calculated by determining which UTXOs were created when the price was lower than the current price (i.e. the price has increased since the UTXOs were created). It represents the total absolute number of those UTXOs.
Rafael Schultze-Kraft - Dissecting Bitcoin's Unrealised On-Chain Profit/Loss