Examine source code of Win 10 Darkest

{
  "name": "Win 10 Darkest",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "UW-Greys_0006_Color-Fill-6 - windows darkest.png"
    },
    "colors": {
      "frame": "rgba(38, 38, 38, 1)",
      "tab_background_text": "rgba(200, 200, 200, 1)",
      "toolbar": "rgba(38, 38, 38, 1)",
      "bookmark_text": "rgba(250, 250, 250, 1)",
      "toolbar_field": "rgba(38, 38, 38, 1)",
      "toolbar_field_text": "rgba(250, 250, 250, 1)"
    }
  }
}