Examine source code of Dark Red Outline

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Dark red",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-004-411c27df18d2f86bd8790aa4a1bde85f.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(43, 44, 56)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(16, 16, 25)",
      "tab_background_text": "rgb(136, 134, 134)",
      "toolbar_field": "rgb(53, 53, 55)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(234, 0, 19)",
      "popup": "rgb(51, 51, 53)",
      "popup_text": "rgb(237, 237, 237)",
      "button_background_active": "rgb(180, 1, 1)",
      "button_background_hover": "rgb(146, 0, 0)",
      "popup_border": "rgb(255, 0, 3)",
      "tab_loading": "rgb(234, 0, 19)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c0da3bfb-9d97-4f65-be80-a5d7873a1846}"
    }
  }
}