It's just a txt file within your mod's Public/Stats/Generated/ folder. Here is what the game uses for the Ranger class equipment, for example:

Code
new equipment "Class_Ranger"
add equipmentgroup 
add equipment entry "WPN_StandardIssueBow"
add equipmentgroup 
add equipment entry "WPN_FightingKnife_B"
add equipmentgroup 
add equipment entry "POTION_Minor_Healing_Potion"
add equipmentgroup 
add equipment entry "POTION_Minor_Healing_Potion"
add equipmentgroup 
add equipment entry "WPN_Arrow_Poison_A"
add equipmentgroup 
add equipment entry "WPN_Arrow_Stunning_A"
add equipmentgroup 
add equipment entry "WPN_Arrow_Fire_A"
add equipmentgroup 
add equipment entry "SCROLL_Resurrect_1"
add equipmentgroup 
add equipment entry "CONT_Backpack_A_SourceHunter"



There's the [new equipment] line at the top that states the name to use in the Editor.

There's the [add equipmentgroup] line between each item.

And then there's [add equipment entry "item"] that states what item it has.