This item is not included in any spawn asset, but it doesn't necessarily mean that it doesn't spawn naturally on any of the maps.
Flamethrower_60.dat
GUID c1cb84a0582b4178a64f601d2f038adc
Type Magazine
Rarity Epic
ID 3091
Size_X 2
Size_Y 1
Size_Z 0.1
Amount 60
Count_Min 60
Count_Max 60
Calibers 1
Caliber_0 70
Projectile_Damage_Multiplier 0.8
Projectile_Launch_Force_Multiplier 0.8
Blueprints 2
Blueprint_0_Type Ammo
Blueprint_0_Supplies 1
Blueprint_0_Supply_0_ID 3091
Blueprint_0_Build 30
Blueprint_1_Type Tool
Blueprint_1_Supplies 4
Blueprint_1_Supply_0_ID 75
Blueprint_1_Supply_0_Amount 1
Blueprint_1_Supply_1_ID 72
Blueprint_1_Supply_1_Amount 2
Blueprint_1_Supply_2_ID 70
Blueprint_1_Supply_2_Amount 3
Blueprint_1_Supply_3_ID 397
Blueprint_1_Supply_3_Amount 2
Blueprint_1_Tool 3090
Blueprint_1_Tool_Critical
Blueprint_1_Level 3
Blueprint_1_Skill Cook
Blueprint_1_Build 27
Delete_Empty