As my local firebomber base a block up the street told me, it is either an
ammonium nitrate or ammonium phosphate base with water, colorant, and something
to make it "sticky".

Nitrate or phosphate base is a function of the supplier of the goo.

Thanks, Jim, but what I meant by "function" is, what does the
phosphate (or nitrate) DO?

Isn't ammonium nitrate the stuff used to make car bombs? If so, why
would it be dropped onto a fire?

"Ammonium" is loaded with hydrogen and "-ate" means lots of oxygen.
Neither would seem to ideal for quenching a fire.

vince norris