English term
Brazil
Quality, commitment and reliability.
Native in: Portuguese (Variant: Brazilian) 
Works in: English to Portuguese, Portuguese to English
shine-through legends
"They are excellent keycaps but I find that I need shine-through legends because I game/work in complete darkness."
Proposed translations
Brazil
32 years engineering/law/contracts
Native in: English (Variant: US) , Portuguese (Variant: Brazilian) 
Works in: English to Portuguese, Portuguese to English
teclas com iluminação interna / teclas com LED
Portugal
Experienced & Qualified Translator EN>PT
Native in: Portuguese (Variant: European/Portugal)
Works in: English to Portuguese, Portuguese to English, Portuguese, and 1 more.
teclas com letras iluminadas
Brazil
Great quality, price, and creativity
Native in: Portuguese (Variant: Brazilian)
Works in: English to Portuguese, Portuguese
caracteres brilhem (VEJA A MINHA TRADUÇÃO DA FRASE)
Will do!
Native in: Portuguese (Variant: European/Portugal)
Works in: English to Portuguese, French to Portuguese, German to Portuguese, and 1 more.
teclas retroiluminadas
Teclas retroiluminadas com deteção de proximidade da mão;
Teclado Universal com 104 Teclas Retroiluminadas para uma Experiência de Jogo Clara e Acessível.
Brazil
IT Specialist • M.A. in Linguistics
Native in: Portuguese (Variant: Brazilian)
Works in: English to Portuguese, Spanish to Portuguese, Portuguese to English, and 1 more.
caracteres translúcidos e iluminados
...light shining through the lettering (aka "Legends")"
É um teclado em que os caracteres são translúcidos e a luz passa por eles :)
https://www.magazineluiza.com.br/kit-gamer-k-mex-teclado-km5...
Caracteres translúcidos
Discussion
Exemplo de teclado que só as teclas brilham: https://www.rotavirtualinfo.com.br/teclado-gamer-led-abnt2-l...