This file is some kind of a cheat code created by EA in order to make the CPU more active at some durations during a match, in other words, it's just like what we call in human world "Adrenaline", which we get from a motivation that we plant in our brains in order to score more and win.
The intensty code is mainly structured of 9 rows and 7 columns, where the rows represent the targeted score in the range of -4 to 4, and the columns are for each period of time going by the multiples of "15" (0, 15, 30... and so on).
Here is more explanation: (I'm going to use my intensty.txt settings for the example)
Let us say that you opened the file intensty.txt, you'll find a code that will look like this:
1 0 1 0 1 0 0
0 1 0 0 1 0 1
0 2 2 1 2 1 3
1 3 1 2 1 1 1
1 2 1 4 3 1 4
1 2 4 2 3 4 3
0 1 2 2 4 2 3
0 1 1 1 2 1 1
0 0 1 1 0 1 0
So what dose these numbers mean? Well, follow on for the answer.
-4 ------- 1 0 1 0 1 0 0
-3 ------- 0 1 0 0 1 0 1
-2 ------- 0 2 2 1 2 1 3
-1 ------- 1 3 1 2 1 1 1
‌‌‌‌+0 -‌------ 1 2 1 4 3 1 4
+1 ------- 1 2 4 2 3 4 3 <---- (For the example bellow)
+2 ------- 0 1 2 2 4 2 3
+3 ------- 0 1 1 1 2 1 1
+4 ------- 0 0 1 1 0 1 0
As you can see, I've picked the 6th row as an example where this 6th row represents the score "1", This row means that at the time "0" to "14" (Column 1) the CPU will give 1 time power to score at least 1 goal, and at the time "15" to "29" the CPU will give 2 times the power to score 1 goal, and at the time "30" to "44" the CPU will give 4 times the power to score 1 goal.
If we chose the 2nd row for example, which is "-3" then at each column timing the CPU will feel that they have already scored 3 goals and will lay back for a little time, but of course they will not lay back too much as there are other rows in that exact column that asks the CPU to spend more power or less. No need to be confused, the CPU does the calculation!
The numbers inside this small matrix are just like the adrenaline levels in the human body, it makes the game more fun and realistic and more AI-ed, it is a very simple matrix to understand, but when tweaked carefully it becomes one of the main elements inside this game, it's what makes the CPU act with some sort of human emotions, sometimes they want to score more and sometimes they want to just lay back and get ready for a later attack.
Peace!