Examine source code of purple red gradient

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "purple red gradient",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(50, 26, 50, 0.88)",
      "toolbar_text": "rgb(219, 202, 206)",
      "frame": "rgb(113, 21, 46)",
      "tab_background_text": "rgb(219, 202, 206)",
      "toolbar_field": "rgb(66, 39, 66)",
      "toolbar_field_text": "rgb(219, 202, 206)",
      "tab_line": "rgb(66, 39, 66)",
      "popup": "rgb(42, 32, 42)",
      "popup_text": "rgb(219, 202, 206)",
      "icons": "rgb(154, 121, 154)",
      "tab_loading": "rgb(66, 39, 66)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f28ecf9b-9303-495b-930e-561530dfb1c3}"
    }
  }
}