Examine source code of Cascade

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "cascade",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(34, 37, 37)",
      "toolbar_text": "rgb(243, 245, 246)",
      "frame": "rgb(18, 23, 23)",
      "tab_background_text": "rgb(177, 184, 185)",
      "toolbar_field": "rgb(18, 23, 23)",
      "toolbar_field_text": "rgb(243, 245, 246)",
      "tab_line": "rgba(243, 245, 246, 0)",
      "popup": "rgb(34, 37, 37)",
      "popup_text": "rgb(243, 245, 246)",
      "popup_highlight": "rgb(34, 37, 37)",
      "toolbar_field_border_focus": "rgba(34, 37, 37, 0)",
      "tab_loading": "rgba(243, 245, 246, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0687eb4b-cc48-47b7-9a13-7ff95883fc5d}"
    }
  }
}