Examine source code of Flack

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Flack",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(23, 23, 23)",
      "toolbar_text": "rgb(212, 212, 212)",
      "frame": "rgb(38, 38, 38)",
      "tab_background_text": "rgb(115, 115, 115)",
      "toolbar_field": "rgb(23, 23, 23)",
      "toolbar_field_text": "rgb(212, 212, 212)",
      "tab_line": "rgb(23, 23, 23)",
      "popup": "rgb(23, 23, 23)",
      "popup_text": "rgb(245, 245, 245)",
      "tab_loading": "rgb(23, 23, 23)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0c8ef388-47e7-458e-82ac-5e0402a7be0e}"
    }
  }
}