Can someone explain what the letters in the () mean when it comes to genetics and what it means if they are in different colors if theres a genetics chart or thread Id love the link thanks

The letters correspond to different genes or mutations for that slot. So for Vulnyxes, Gene 1, the letter A is for Cheetah spots and the letter B is for Tiger stripes. Letters higher up in the alphabet are more dominant than lower down letters so if a sylesti had AB then the A mutation/gene would be visible and the B one would be hidden. The letter N means nothing and isn't a trait. Green means the trait is hidden, purple means there 2 different traits in that slot, blue means that the two slots are the same i.e. AA or BB
This thread might explain it better
https://www.sylestia.com/forums/?thread=370

Thank you do very much