Examine source code of simplify dark

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "simple dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-001-9c6d74e14860e77ee6f8f43e824bff25.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(15, 15, 15)",
      "toolbar_text": "rgb(221, 221, 221)",
      "frame": "rgb(34, 34, 34)",
      "tab_background_text": "rgb(193, 193, 193)",
      "toolbar_field": "rgb(15, 15, 15)",
      "toolbar_field_text": "rgb(221, 221, 221)",
      "tab_line": "rgba(0, 0, 0, 0)",
      "popup": "rgb(15, 15, 15)",
      "popup_text": "rgb(221, 221, 221)",
      "ntp_background": "rgb(15, 15, 15)",
      "ntp_text": "rgb(221, 221, 221)",
      "popup_border": "rgba(15, 15, 15, 0)",
      "sidebar_border": "rgba(15, 15, 15, 0)",
      "sidebar_text": "rgb(221, 221, 221)",
      "sidebar": "rgb(15, 15, 15)",
      "tab_loading": "rgba(0, 0, 0, 0)"
    }
  }
}