This file defines minimum stats (Str,Dex etc.) per class/kit. The first row (titles of columns ) is filled by the names of defined characteristics of PC (like MIN_STR = minimal strength ). The first column is filled by class/kits names. The crossings of the certain identifiers indicate if class/kit could be used with the characteristic of PC - used for character creation.
In IWD: TotL we have:

2DA V1.0
0
                      MIN_STR    MIN_DEX    MIN_CON    MIN_INT    MIN_WIS    MIN_CHR    
MAGE                  0          0          0          9          0          0          
FIGHTER               9          0          0          0          0          0          
CLERIC                0          0          0          0          9          0          
THIEF                 0          9          0          0          0          0          
BARD                  0          12         0          13         0          15         
PALADIN               12         0          9          0          13         17         
DRUID                 0          0          0          0          12         15         
RANGER                13         13         14         0          14         0          
FIGHTER_MAGE          9          0          0          9          0          0          
FIGHTER_CLERIC        9          0          0          0          9          0          
FIGHTER_THIEF         9          9          0          0          0          0          
FIGHTER_MAGE_THIEF    9          9          0          9          0          0         
MAGE_THIEF            0          9          0          9          0          0          
CLERIC_MAGE           0          0          0          9          9          0          
CLERIC_THIEF          0          9          0          0          9          0          
FIGHTER_DRUID         9          0          0          0          12         15         
FIGHTER_MAGE_CLERIC   9          0          0          9          9          0         
CLERIC_RANGER         13         13         14         0          14         0          
ABJURER               0          0          0          9          15         0          
CONJURER              0          0          15         9          0          0          
DIVINER               0          0          0          9          16         0          
ENCHANTER             0          0          0          9          0          16         
ILLUSIONIST           0          16         0          9          0          0          
INVOKER               0          0          16         9          0          0          
NECROMANCER           0          0          0          9          16         0          
TRANSMUTER            0          15         0          9          0          0