Great question — answering as the UphillTech team:
The kind of trooper is actually an Incinerator Trooper /Incinerator Stormtrooper/"Burner", which are a higher and/or more lethal corp classification. Incinerator troopers, also known as the Incinerator Stormtroopers, more simply as the Incinerators, or colloquially as the Burners were a class of stormtrooper within the Imperial Stormtrooper Corps which wielded powerful flamethrower weaponry. The troopers received intense fire combat training and were regarded as one of the most devastating of the Corps' specialized contingents , setting enemies and their fortifications ablaze with their flamethrower equipment. Stormtroopers of this class were equipped with standard issue stormtrooper armor...
Full answer by Darth Locke: https://movies.stackexchange.com/a/120010 (CC BY-SA 4.0).
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