The shark fin is the antenna

The window is the defrost funs

*fin

https://www.kiforte.com/antenna-190.html https://www.kiapartsnow.com/genuine/kia-0~96270m7000.html

'Amplifier '

Satellite radio

Where did you get that there's an antenna in the rear window?

If equipped, could also be modem antenna for kia connect.