Examine source code of rb basic

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "the silly",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-024-8de86d890779309c9a66423c64daa480.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(24, 46, 70)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(98, 0, 6)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(15, 31, 47)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(255, 0, 54)",
      "popup": "rgba(115, 0, 40, 0.89)",
      "popup_text": "rgb(255, 255, 255)",
      "tab_selected": "rgb(177, 0, 37)",
      "tab_loading": "rgb(255, 0, 54)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{af8c4568-76a2-4e26-b257-008278172b75}"
    }
  }
}