This file defines intelligence influence on characters abilities like success in spell learning or max possible maximal spells level that can be obtained by creature.
The first row (titles of columns ) is filled by the names of features affecting of PC (like LEARN_SPELL).
The first column is filled by value of intelligence of character.
The rest columns are filled by values for given intelligence - pretty obvious from names I suppose.

In PSTEE we have:

2DA V1.0
0
    LEARN_SPELL     MAX_SPELL_LEVEL     MAX_SPELLS_PER_LEVEL
0   0               0                   0
1   0               0                   0
2   0               0                   0
3   0               0                   0
4   0               0                   0
5   0               0                   0
6   0               0                   0
7   0               0                   0
8   0               0                   0
9   100             4                   6
10  100             5                   7
11  100             5                   7
12  100             6                   7
13  100             6                   9
14  100             7                   9
15  100             7                   11
16  100             8                   11
17  100             8                   14
18  100             9                   18
19  100             9                   100
20  100             9                   100
21  100             9                   100
22  100             9                   100
23  100             9                   100
24  100             9                   100
25  100             9                   100