There are some tools for coloring and summarising combat reports, making them easier to read.
When you receive a combat report, the subject line says, for example,
Combat Report (5,130) [1:1:1] (V:400000,A:1000)
Inside the first brackets it shows (number of rounds in the battle, number of ships left) so in this battle there were 5 rounds and 130 ships left. The number of rounds is always shown as (number of rounds-1) with a min of 0 and a max of 5.
Inside the square brackets it shows the co-ordinates that the attack took place at.
Inside the other brackets it shows what both sides lost in Units (1 resource = 1 unit)
V = person who was attacked
A = person attacking.
So in this case the attacker lost 1000 units and the defender lost 400,000.