Examine source code of neon rainbow

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "neon rainbow",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(26, 26, 27)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(26, 26, 27)",
      "tab_background_text": "rgb(147, 147, 147)",
      "toolbar_field": "rgb(243, 112, 159)",
      "toolbar_field_text": "rgba(18, 18, 20, 0.65)",
      "tab_line": "rgba(102, 102, 194, 0)",
      "popup": "rgb(226, 221, 106)",
      "popup_text": "rgb(26, 26, 27)",
      "icons_attention": "rgb(226, 221, 106)",
      "icons": "rgb(147, 147, 147)",
      "ntp_background": "rgb(18, 18, 20)",
      "ntp_text": "rgb(147, 147, 147)",
      "popup_border": "rgba(147, 147, 147, 0)",
      "sidebar_highlight": "rgb(114, 211, 252)",
      "sidebar_text": "rgb(255, 255, 255)",
      "sidebar": "rgb(26, 26, 27)",
      "tab_loading": "rgb(243, 112, 159)",
      "toolbar_bottom_separator": "rgba(26, 26, 27, 0)",
      "toolbar_field_highlight": "rgb(114, 211, 252)",
      "toolbar_field_text_focus": "rgb(255, 255, 255)",
      "toolbar_top_separator": "rgba(26, 26, 27, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{310b20ba-a479-4acf-80d0-1b5cdc2340d4}"
    }
  }
}