On: ZSA Planck EZ: A Powerful, Backlit, Open-Source, 40% Mechanical Keyboard

[smrq]

Those are usually hand-wired (otherwise you need some sort of flex PCB design, which I have seen but it's uncommon) and that makes individual LEDs a huge pain at best.

[rgoulter → smrq]

I think the ones which have fancy RGB LEDs will use a 1U-sized PCB to allow for lighting.