Examine source code of Mostly Blue

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Mostly Blue",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(48, 68, 113)",
      "toolbar_text": "rgb(213, 227, 255)",
      "frame": "rgb(72, 93, 139)",
      "tab_background_text": "rgb(200, 213, 240)",
      "toolbar_field": "rgb(72, 93, 139)",
      "toolbar_field_text": "rgb(200, 213, 240)",
      "tab_line": "rgb(73, 99, 246)",
      "popup": "rgb(48, 68, 113)",
      "popup_text": "rgb(200, 213, 240)",
      "button_background_active": "rgba(0, 0, 0, 0.3)",
      "button_background_hover": "rgba(0, 0, 0, 0.2)",
      "icons_attention": "rgb(103, 134, 254)",
      "ntp_background": "rgb(200, 213, 240)",
      "ntp_text": "rgb(26, 44, 86)",
      "popup_border": "rgb(26, 44, 86)",
      "popup_highlight": "rgb(60, 80, 125)",
      "sidebar_border": "rgb(26, 44, 86)",
      "sidebar_highlight": "rgb(72, 93, 139)",
      "sidebar_text": "rgb(200, 213, 240)",
      "sidebar": "rgb(48, 68, 113)",
      "tab_loading": "rgb(73, 99, 246)",
      "tab_text": "rgb(200, 213, 240)",
      "toolbar_field_border_focus": "rgb(80, 107, 223)",
      "toolbar_field_highlight_text": "rgb(213, 227, 255)",
      "toolbar_field_highlight": "rgb(91, 120, 238)",
      "toolbar_field_text_focus": "rgb(200, 213, 240)"
    }
  }
}