Examine source code of soft rainbow gradient

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "soft rainbow gradient",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 151, 147, 0.1)",
      "toolbar_text": "rgba(217, 245, 156, 0.85)",
      "frame": "rgb(211, 62, 158)",
      "tab_background_text": "rgb(66, 64, 70)",
      "toolbar_field": "rgba(217, 229, 174, 0.5)",
      "toolbar_field_text": "rgba(34, 8, 62, 0.6)",
      "tab_line": "rgba(255, 210, 238, 0.7)",
      "popup": "rgb(224, 242, 232)",
      "popup_text": "rgb(104, 82, 61)",
      "button_background_active": "rgba(230, 121, 162, 0.5)",
      "button_background_hover": "rgba(200, 255, 240, 0.2)",
      "icons_attention": "rgb(255, 133, 68)",
      "icons": "rgba(149, 255, 206, 0.7)",
      "ntp_background": "rgb(255, 238, 243)",
      "ntp_text": "rgb(143, 110, 101)",
      "popup_border": "rgba(70, 207, 225, 0.6)",
      "popup_highlight_text": "rgba(188, 122, 0, 0.85)",
      "popup_highlight": "rgba(255, 252, 210, 0.75)",
      "sidebar_border": "rgb(229, 192, 155)",
      "sidebar_highlight_text": "rgb(218, 78, 177)",
      "sidebar_highlight": "rgb(242, 249, 248)",
      "sidebar_text": "rgba(21, 5, 38, 0.6)",
      "sidebar": "rgb(224, 237, 207)",
      "tab_loading": "rgb(126, 116, 227)",
      "tab_selected": "rgba(255, 181, 213, 0.25)",
      "tab_text": "rgb(193, 0, 137)",
      "toolbar_bottom_separator": "rgba(74, 88, 105, 0.5)",
      "toolbar_field_border_focus": "rgba(238, 154, 169, 0.7)",
      "toolbar_field_focus": "rgba(192, 237, 210, 0.91)",
      "toolbar_field_highlight_text": "rgb(228, 255, 219)",
      "toolbar_field_highlight": "rgb(33, 217, 222)",
      "toolbar_field_text_focus": "rgba(14, 3, 25, 0.6)",
      "toolbar_top_separator": "rgba(229, 52, 169, 0.25)",
      "toolbar_vertical_separator": "rgba(220, 237, 197, 0.5)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8a9b494c-997c-483f-b029-1f0eeb59c9aa}"
    }
  }
}