Examine source code of Apple Dark

{
  "name": "Apple Dark",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Screenshot 2020-10-11 at 23.37.14.png"
    },
    "colors": {
      "frame": "rgba(28, 28, 30, 1)",
      "tab_background_text": "rgba(229, 229, 234, 1)",
      "toolbar": "rgba(199, 199, 204, 1)",
      "bookmark_text": "rgba(229, 229, 234, 1)",
      "toolbar_field": "rgba(229, 229, 234, 1)",
      "toolbar_field_text": "rgba(28, 28, 31, 1)"
    }
  }
}