In this window you can view content of internal NAT table in real time. Each row contains the rule name by which entry is created, protocol, source and destination addresses and ports, time from the moment of creation.

Active items marked with green "arrows". Waiting items marked with "clock" image.

In some cases NAT table can contain many thousands items, but you can change value of maximum returned rows (by default - 100 rows) and apply filters by rule name or by source IP address. Masks allowed (like "*" or "?").