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 BG1 TotS 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