iptables-save output:
*filter
:INPUT DROP [2929:172650]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [74596344:6265371965]
These are the opening lines of the iptables-save command. What do the numbers in the square brackets mean?
They are the packet counter and byte counter that you can get live with the iptables -L -v command.
Examples and explanations can be found in the Iptables Tutorial - iptables-save document.