Examine source code of Brown book

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Coffee shop",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-006-51ab495c5f5dde6a3cddb22484acd00d.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(241, 240, 234)",
      "toolbar_text": "rgb(20, 11, 1)",
      "frame": "rgb(75, 59, 41)",
      "tab_background_text": "rgb(213, 206, 199)",
      "toolbar_field": "rgb(54, 48, 48)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(49, 189, 127)",
      "popup": "rgb(45, 40, 27)",
      "popup_text": "rgb(168, 166, 161)",
      "tab_loading": "rgb(49, 189, 127)"
    }
  }
}