Examine source code of The Blue Danube

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Blue Danube",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(1, 97, 230)",
      "toolbar_text": "rgb(63, 210, 231)",
      "frame": "rgb(142, 179, 201)",
      "tab_background_text": "rgb(180, 202, 205)",
      "toolbar_field": "rgb(81, 134, 209)",
      "toolbar_field_text": "rgb(13, 247, 212)",
      "tab_line": "rgb(4, 61, 254)",
      "popup": "rgb(21, 35, 224)",
      "popup_text": "rgb(63, 210, 231)",
      "tab_loading": "rgb(4, 61, 254)"
    }
  }
}