There you are:
Data - generation count - the maximum value of spawns generated from summoned fire spawn (per cast). Means that if for lvl1 its 3, your summonem unit will generate at first one additional spawn, and then both of them can split once again, giving a total amount = 4.
Data - life duration split bonus - increases expiration timer on splitting spawn when split is done, the new created unit has the same duration as the one it was created from.
Data - max hitpoint factor - value of life our spawn can get back after splitting. It's set by default to 0.5. If our spawn is close to die while splitting, it recovers nearby 50% of its own max health. The higher current life of splitting spawn is, the lower recovered health bonus will be.
Spawned unit shares the same life value of it's creator.
Data - split delay - its a timer, that discribes how much time the splitting will take. Splitting means here ofcourse creating new spawns.
Data - split attack count - the amount of attacks needs to be done before spawn is able to split. Missles that didnt cause dmg dont count.
Data - summoned unit count - amount of units of given type, spell will summon instantly after casting of the ability is done.
Data - summoned unit type - unit type this spell will summon within each cast.
There is also the duration, which tells the initial duration of summoned unit.