A few thoughts on ‘anarchist warfare’ and ‘statist warfare’.
In normal wars (though to varying degrees), the contest is between two or more territory-controlling forces. The activity of ‘controlling’ territory is distinct from the activity of living there; the contending forces are thus distinct from the populations inhabiting the areas fought over (again, to varying degrees). Consequently, the inhabiting population tends to appear as a passive ‘background’, as what is ‘fought over’.
As long as this pattern is in place, I would call the conflict ‘statist’ regardless of whether it’s one ‘official’ state against another, one ‘rebel’ group against another, an established government against rebels, etc. The point is, insofar as the dynamic of the war divides the population in general from the contending forces, and makes one passive and the other active, the essential dynamics of statehood are in play.
So what would an anarchist war look like? The ideal (however closely it is or isn’t acheived) is that this division between warring force and local population not exist. That is, the ideal would be that the activity of ‘controlling’ territory be simply an aspect of living there; that local populations at each point be actively organised to maintain something like a ‘monopoly of violence’ in that area.