Hmm, it looks like they're not showing in the INFO section properly. The "vanilla default" for incendiary is 5-10 damage, anything other than that for fire weapons is modded and will show up properly. The "FireBlastCalc" determines how incendiary explosives turn power into radius; the default for area-of-effect weapons is 1 tile per 10 power, but incendiary damage type has half this radius. These calculations are from the original game, so you can assume that any incendiary weapon will do this unless stated otherwise in the INFO section without any of the modifier buttons turned on.