Looking through the v1.5.1 PayPal Express Checkout module (/includes/modules/payment/paypalwpp.php), there's a configuration key (MODULE_PAYMENT_PAYPALWPP_EC_RETURN_FMF_DETAILS) to enable the Fraud Management Filter interface with PayPal but it's never actually displayed in the admin because it's not present in the array returned by the keys() function of the class.

Is this a simple omission or is the control not made available because the FMF interface hasn't been fully fleshed out?