Quick comment describing need for IPN TZ adjustment

CRM/Core/Payment/PayPalIPN.php

@@ -394,6 +394,10 @@ public function getInput(&$input, &$ids) {
     $paymentDate = $this->retrieve('payment_date', 'String', FALSE);
     if (!empty($paymentDate)) {
       $receiveDateTime = new DateTime($paymentDate);
+      /**
+       * The `payment_date` that Paypal sends back is in their timezone. Example return: 08:23:05 Jan 11, 2019 PST
+       * Subsequently, we need to account for that, otherwise the recieve time will be incorrect for the local system
+       */
       $systemTimeZone = new DateTimeZone(CRM_Core_Config::singleton()->userSystem->getTimeZoneString());
       $receiveDateTime->setTimezone($systemTimeZone);
       $input['receive_date'] = $receiveDateTime->format('YmdHis');