Best AOE Target

[Burle17]

can you say a few words about how this logic behind this works? does it just select that one with the most health or nearest or so?

[Lynesth]

It checks all targets on screen and for each of those it checks how many other targets are in a 5 yalm radius of their center.
It will pick the one that allows you to hit the highest number of targets. In case of a tie, it'll pick the one with the most current HP among those who are tied.