Just started playing so i don't think the actual hand lantern is in this but that's what it basically is. If you charge a heavy attack then use a molotov anytime during the animation you'll pull out a bottle but will be interrupted by the attack and won't throw it. This will leave a fire effect over the hunter's waist that produces light. It's real easy to do, doesn't consume the molotov, frees up the left hand for a gun instead of the torch. effect breaks if you use a molotov like normal (still has fire effect but no light) and completely disappears after a load screen.
Not sure if I want this to be patched out as it's relatively harmless but makes the torch less useful