With the V5.3 update, there have been a lot of files added to Fortnite and it looks like new weapons have been added, according to leaker @FNBRLeaks. There are files that suggest the Flamethrower and Quad Launcher, which is in Save the World, could be added to Fortnite Battle Royale:
There isn’t much information on the Flamethrower, but these are the files that have been found:
Currently, the Flamethrower files is showing it’s an “LMG” and uses Medium Bullets. It is more than likely that there will be a lot of changes to the Flamethrower files before it is added to Fortnite Battle Royale, if it is added.
There has not been any official announcement by Epic on these weapons, but we will let you know if changes are made.