It a loaded topic with lots of room for discussion, but essentially, it's not that much about
design of a character, but about how they're
portrayed.
Male gaze is the avareness of the person depicted in an art form, to being seen by a viewer and involving them in some capacity.
Early examples of the male gaze are found in nude painting from the Reinassance. When nude women are painted to look at the viewer looking at
them the painting. Like this one:

It's designed in a way where the woman's attention is directed at the viewer, instead of whatever she's engaged in (this also goes for paintings where they're drawn engaging with lovers). It implies that she isn't nude for her own sake but for the viewers sake, to be
displayed.
That sketch fromn Timm with Harley and Ivy
is male gaze, but not because of their designs, but because 1. Harley's crotch is facing the viewer despite jot needing to, and 2., because they're ''adressing'' the viewer by looking and talking to them - thus ''involving'' the viewer.
It has nothing to do with their designs, those are fucking neat.
Things get more complicated with movies and comics, where the viewer is the camera/frame.
Eat, Bang, Kill is a weird example of this, because it has so many fourth wall breaks and it's written in a way where the characters are constantly aware that they're being watched.
I wanted to get this of my chest.