Question Optical switc in keyboards

Keychron K6 can have optical switches and those are hot-swappable as well. So, optical is part of the key switch and not the board.
Specs: https://www.keychron.com/products/keychron-k6-wireless-mechanical-keyboard

Keychron K7 is the slim version, while also offering optical hot-swappable switches,
specs: https://www.keychron.com/products/keychron-k7-ultra-slim-wireless-mechanical-keyboard

Asus TUF Gaming K7 also has optical switches,
specs: https://www.asus.com/accessories/keyboards/tuf-gaming/tuf-gaming-k7/
 
Best I can find the switches I see the LED and the photo-sensitive element are soldered on the PCB under the key. Do you have a fefferance that shows otherwise? I had a herd time finding pics. May be later modals are like you say.
Thank you, g