Talk: Environment variables

I have the following in my configuration:

   environment.variables = rec {
   EDITOR = "nvim";
   VISUAL = "nvim";
   XDG_DATA_HOME = "\${HOME}/.local/share";
   XDG_CONFIG_HOME = "$HOME/.config";
   XDG_CACHE_HOME = "$HOME/.cashe";
   XDG_STATE_HOME = "$HOME/.local/share";
   ANDROID_SDK_ROOT = "\${XDG_DATA_HOME}/android";
   };

What is then `ANDROID_SDK_ROOT` after rebuild? `/android` Do you have any idea, why this might be?