Examine source code of Colourful Dark

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "Colourful Dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-020-48c286b34e53380d46803c2e5603a5b2.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(4, 10, 10)",
      "toolbar_field": "rgb(22, 44, 55)",
      "toolbar_field_text": "rgb(255, 246, 0)",
      "tab_line": "rgb(99, 247, 99)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(240, 162, 152)",
      "tab_loading": "rgb(99, 247, 99)",
      "bookmark_text": "rgb(112, 217, 225)",
      "frame": "rgb(48, 48, 18)",
      "tab_background_text": "rgb(222, 243, 255)"
    }
  }
}