baseLayoutKey property
Base layout key
From Kitty documentation: The base layout key is the key corresponding to the physical key in the standard PC-101 key layout. So for example, if the user is using a Cyrillic keyboard with a Cyrillic keyboard layout pressing the ctrl+ะก key will be ctrl+c in the standard layout. So the terminal should send the base layout key as 99 corresponding to the c key.
Implementation
final int baseLayoutKey;