Examine source code of Pure Neutral

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "pure-neutral",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(128, 128, 128)",
      "toolbar_text": "rgb(184, 184, 184)",
      "frame": "rgb(128, 128, 128)",
      "tab_background_text": "rgb(187, 187, 187)",
      "toolbar_field": "rgb(245, 245, 245)",
      "toolbar_field_text": "rgb(20, 20, 20)",
      "tab_line": "rgb(90, 90, 90)",
      "popup": "rgb(82, 89, 205)",
      "popup_text": "rgb(246, 246, 246)",
      "button_background_active": "rgb(157, 157, 157)",
      "icons_attention": "rgb(101, 237, 76)",
      "ntp_background": "rgb(179, 179, 179)",
      "popup_border": "rgb(90, 90, 90)",
      "sidebar_border": "rgb(255, 253, 86)",
      "sidebar_highlight_text": "rgb(48, 48, 48)",
      "sidebar_highlight": "rgb(248, 248, 248)",
      "sidebar_text": "rgb(35, 35, 35)",
      "sidebar": "rgb(255, 243, 86)",
      "tab_selected": "rgb(142, 142, 142)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgb(98, 98, 98)",
      "toolbar_field_border_focus": "rgb(86, 86, 86)",
      "toolbar_field_border": "rgb(90, 90, 90)",
      "toolbar_field_highlight": "rgb(39, 143, 215)",
      "toolbar_top_separator": "rgb(128, 128, 128)",
      "tab_loading": "rgb(90, 90, 90)"
    }
  }
}