Looks like the frame left the fuselage. Bad workmanship. Can you imagine sitting next to that when it blows out, trying to suck you out with it? And airlines have the audacity to charge extra for that ‘extra legroom seat’. All you do is certify you are fit and able to open the emergency exit if needed and directed.
Hawaii is still the ‘fuselage blowout’ capital with two: United 747 in the 80s, and Aloha 737 ‘pop top’ at Maui.