Examine source code of Boki book

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Boki book",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-043-dfcec5f93f7a29f97b030eda45530203.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(225, 234, 239)",
      "toolbar_text": "rgb(45, 183, 86)",
      "frame": "rgb(46, 117, 159)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(225, 234, 239)",
      "toolbar_field_text": "rgb(123, 127, 204)",
      "tab_line": "rgb(248, 112, 140)",
      "popup": "rgb(201, 208, 215)",
      "popup_text": "rgb(46, 57, 223)",
      "tab_loading": "rgb(248, 112, 140)"
    }
  }
}