M4A3FL (USA, Tier-7, Heavy Flamethrower Tank, techtree)
Historical Reference:
The US military approached the issue of creating flamethrower tanks after the start of World War II. In the summer of 1942, the Chemical Warfare Service (CWS) began testing tank flamethrowers, in particular, a special flamethrower version of the Medium Tank M4A3. This model received a new welded turret and additional armor protection for the hull. However, the project, which never received a special designation, did not advance beyond the concept. 
