you might want to try linking @variable to Identifier, i think the original author decided to keep @variable unhighlighted to keep the color diff between having

you might want to try linking @variable to Identifier, i think the original author decided to keep @variable unhighlighted to keep the color diff between having `termguicolors` on/off to a minimum (Identifier assumes `termguicolors` is enabled, but for default colorscheme it's likely not always the case). see https://github.com/neovim/neovim/pull/26334 https://github.com/neovim/neovim/pull/26334 and the comments in highlight_group.c