Examine source code of grassland theme

{
  "name": "grassland-theme",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "grassland-theme.png"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(25, 45, 227, 1)",
      "toolbar": "rgba(143, 114, 8, 1)",
      "bookmark_text": "rgba(66, 47, 237, 1)",
      "toolbar_field": "rgba(170, 176, 7, 1)",
      "toolbar_field_text": "rgba(206, 211, 235, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{57aaa607-7f40-47f6-bfe1-96d6c6d6d185}"
    }
  }
}