Examine source code of Soft sunset

{
  "name": "Soft sunset",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "landscape.png"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(179, 129, 84, 1)",
      "toolbar_field_text": "rgba(179, 129, 84, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a49aecf3-3c58-4985-9473-acce47209ced}"
    }
  }
}