Examine source code of Elementary Shadow

{
  "name": "Elementary Dark",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "colour__.png"
    },
    "colors": {
      "frame": "rgba(59, 63, 69, 1)",
      "tab_background_text": "rgba(219, 219, 219, 0.43)",
      "toolbar": "rgba(59, 63, 69, 1)",
      "toolbar_field": "rgba(0, 0, 0, 0.21)",
      "toolbar_field_text": "rgba(255, 255, 255, 0.35)"
    }
  }
}