This file defines modification to stats (Str,Dex etc.) at character creation.
The first row (titles of columns ) is filled by the names of defined characteristics of PC (like MOD_STR = strength modifier).
The first column is filled by race names.
The crossings of the certain identifiers indicate what advantages /penalties receive PC with chosen race - used for character creation.
In BG2 ToB we have:

2DA V1.0
0
            MOD_STR MOD_DEX MOD_CON MOD_INT MOD_WIS MOD_CHR
HUMAN       0       0       0       0       0       0
DWARF       0       0       1       0       0       -1
ELF         0       1       -1      0       0       0
GNOME       0       0       0       1       -1      0
HALF_ELF    0       0       0       0       0       0
HALFLING    -1      1       0       0       0       0
HALFORC     1       0       1       -2      0       0