Examine source code of Dark gray

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Darl gray",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-030-0f935cfde055600d01a959c5c15353de.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(31, 41, 55)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(17, 24, 39)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(107, 114, 128)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(107, 114, 128)",
      "popup": "rgb(31, 41, 55)",
      "popup_text": "rgb(255, 255, 255)",
      "tab_loading": "rgb(107, 114, 128)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{203222ec-660c-4652-833d-d6c71f97d70d}"
    }
  }
}