My guess is a reaction diffusion simulation

Yeah the code has a (somewhat rudimentary) fluid sim that's fed into reaction-diffusion. Pretty cool, don't think I've seen that combination before

I happened to have just finished writing a thesis on such a combination. The size of the little droplets is determined by the chemical wavelength of the reaction-diffusion subsystem. There’s a nice video and a pdf here: https://maximzuriel.nl/dynamics-and-pattern-formation-in-act...