For better or worse, one of the defining characteristics of Power Girl is her costume. The DC Comics character's look features the infamous boob window, which at first glance defies explanation. Well, Geoff Johns once tried to explain why Power Girl's suit has a 'window' in the chest, and... it's something else.
Power Girl first appeared in All Star Comics #58, as Karen Starr, another earth's version of Kara Zor-El aka Supergirl. With all the same powers as Supergirl, Power Girl became a more mature version of the character who fought alongside the Justice Society of America. Power Girl has short hair, a white spandex outfit along with a red cape. One major difference between Supergirl and Powergirl is how overtly sexualized the latter is, with no example more obvious that what many refer to as her signature 'boob window.' Honestly, it's one of the least practical superhero suits in comics.
There have been some attempts at explaining the window over Power Girl's cleavage, with Justice League Europe #37 showing Power Girl explain she is unapologetic about the costume showing her female attributes. The costume even caused debate at DC Comics. But Geoff Johns' attempt to offer an explanation in JSA Classified #2 remains one of the more hilarious attempts. Johns tried to make Power Girl's window tragic. In the comic, Power Girl has a bit of an existential crisis when she runs into Superman. She explains the reason for the window isn't that she is trying to be lewd, but that she wanted a symbol over her own breast... but never figured one out. Yes, that really is what happened.
The issue does dive deeper into Power Girl's identity and stepping out of Supergirl's shadow. So, while the intentions were probably good, the explanation is borderline nonsense. Why wouldn't Power Girl fill in the window with more fabric if she couldn't find a symbol? It's explaining something that already has an explanation. Power Girl's boob window exists to sexualize the character. There doesn't need to be a deep meaning to explain the design choice, or offer an excuse to keep using it. In fact (as revealed to Comics Bulletin) Power Girl co-creator Wally Wood kept drawing her breasts bigger and bigger until DC editorial stopped him.
Just because Power Girl has the egregious design choice now part of her iconic look, that doesn't mean she can't be or hasn't been an interesting hero. Jimmy Palmiotti, Justin Graw, Amanda Conner, and Paul Mounts' Power Girl arc was a lot of fun. But it also didn't try to explain something silly with something dramatic or tragic. It embraced Power Girl and all that she is. Johns is an all-star writer, but this panel is probably one even he might take back.
Over the years Power Girl's original costume has come and gone. Regardless of its prominence in DC Comics, the costume will always be part of the character. And if you need one of DC's best writers to try to change the entire reasoning behind the suit... maybe it's time to just change the suit, instead..