Examine source code of Clean Metro Dark

{
  "name": "Clean Metro Dark",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "bkg.png"
    },
    "colors": {
      "frame": "rgba(31, 31, 31, 1)",
      "tab_background_text": "rgba(217, 217, 217, 1)",
      "toolbar": "rgba(51, 51, 51, 1)",
      "bookmark_text": "rgba(217, 217, 217, 1)",
      "toolbar_field": "rgba(51, 51, 51, 1)",
      "toolbar_field_text": "rgba(217, 217, 217, 1)"
    }
  }
}