Examine source code of Blue Box

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Blue Box",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-009-f069b97f439938a011297c84464f0df6.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(70, 102, 131)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(35, 58, 67)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(62, 62, 78)",
      "tab_line": "rgb(4, 165, 255)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(48, 51, 59)",
      "tab_loading": "rgb(4, 165, 255)"
    }
  }
}