Examine source code of grayblue theme

{
  "manifest_version": 2,
  "version": "2.1",
  "name": "grayblue theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(19, 34, 42)",
      "toolbar_text": "rgb(61, 209, 212)",
      "frame": "rgb(34, 43, 53)",
      "tab_background_text": "rgb(218, 220, 219)",
      "toolbar_field": "rgb(51, 51, 61)",
      "toolbar_field_text": "rgb(249, 249, 249)",
      "tab_line": "rgb(33, 116, 189)",
      "popup": "rgb(8, 19, 16)",
      "popup_text": "rgb(70, 165, 205)",
      "tab_loading": "rgb(33, 116, 189)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1a9ef679-8691-4e1f-8c94-96b5c0914272}"
    }
  }
}