It mentions ethanoic acid, which is the systematic name for what is colloquially known as acetic acid.

What upon earth
Cas-No 64-19-7
and
EINECS-No 200-580-7
and
C.I acid
are, and their role in the preparation, I have absolutely no idea.
But the citric acid and phosphate ester are probably merely to give stability to the preparation.
It is perhaps odd to use a systematic name for the acetic acid, but a colloquial name for the citric acid. But given the systematic name of citric acid is 2-hydroxypropane-1,2,3-tricarboxylic acid, perhaps we can forgive them.

I would also be interested in knowing what people's experience with this product is. It is supposed also to deal with moss as well as algae, and I have a problem with both, the algae more particularly in the more shaded areas. I have a large area paved with fired clay (not concrete) paviours at my drive and front of house, which attracts algae and moss both more luxuriantly, and holds onto it better, than the concrete ones. Last time I gave it a good clean (with a pressure washer) it took a couple of days, since one had to give detailed attention to every individual brick, an experience I am keen not to repeat. So if this stuff is as effective as they claim, it would be a huge boon.